PIC 24F as an I2C slave has lock up issues sending multiple data bytes to the master (MASTER READ).
The PIC (specifically 24FJ128GB202) as an I2C slave receiving data (MASTER WRITE) works perfectly, passing all unit tests. (address only, address and register, address register single data and multiple data auto increment)
My slave code can handle address-only and reading a single byte. It hangs on multiple reads made from the master (auto increment).
I used the Microchip app note as the basis of my code, as well as looking at the Code Composer generated code.
Initialization:
void I2C1_Initialize(void)
{
I2C1ADD = I2C1_SLAVE_ADDRESS;
I2C1MSK = I2C1_SLAVE_MASK;
I2C1CONL = 0x8200;
I2C1CONH = 0x0000;
I2C1STAT = 0x0000;
// clear the master interrupt flag
IFS1bits.SI2C1IF = 0;
// enable the master interrupt
IEC1bits.SI2C1IE = 1;
}
Interrupt Write:
// clear the interrupt
_SI2C1IF = 0;
// Write from Master to Slave - Address
// S = 1, D_A = 0, R_W = 0, BF = 1
if ( (I2C1STATbits.S == 1) && (I2C1STATbits.D_A == 0) && (I2C1STATbits.R_W == 0) && (I2C1STATbits.RBF == 1) )
{
myI2CAd = I2C1RCV;
mySTATE = 0;
}
// Write from Master to Slave - Data
// S = 1, D_A = 1, R_W = 0, BF = 1
if ( (I2C1STATbits.S == 1) && (I2C1STATbits.D_A == 1) && (I2C1STATbits.R_W == 0) && (I2C1STATbits.RBF == 1))
{
mySTATE++;
if(mySTATE == 1)
{
myREGISTER = I2C1RCV;
// limit register to MAX
if(myREGISTER > I2CMAXREGISTER) myREGISTER = I2CMAXREGISTER;
}
if(mySTATE == 2)
{
myDATA = I2C1RCV;
shelfregister[myREGISTER] = myDATA;
}
if(mySTATE > 2)
{
myDATA = I2C1RCV;
// limit register to MAX
if(myREGISTER < I2CMAXREGISTER) myREGISTER++;
shelfregister[myREGISTER] = myDATA;
}
}
Interrupt Read:
// Read from Slave to Master - Address
// S = 1, D_A = 0, R_W = 1, BF = 0
if ( (I2C1STATbits.S == 1) && (I2C1STATbits.D_A == 0) && (I2C1STATbits.R_W == 1) && (I2C1STATbits.TBF == 0) )
{
myI2CAd = I2C1RCV;
I2C1TRN = shelfregister[myREGISTER];
I2C1CONLbits.SCLREL = 1;
if(myREGISTER < I2CMAXREGISTER) myREGISTER++;
}
The code generated by the Code Composer for slave operation is quite similar and has the same issue.
My main question is how to handle multiple reads from the master, not just the single byte that is handled in this read function. It should involve checking I2CSTATbits.ACKSTAT, but the timing of that bit is unclear to me since it should happen 9 clocks after the byte is in the register, but there is no bit to indicate that point in time. Any guidance appreciated.
Related
This is rather ugly. We're getting weird hangups caused (read: triggered) by some security scanning software. I suspect it has a nonstandard TCP/IP stack, and the customer is asking why hangups.
Static analysis suggests only two possible locations for the hangup. The hangup either has to be in ReadFile() or WriteFile() on a socket; and WriteFile() cannot hang here unless the scanner is designed to make WriteFile() hang by setting the window size to zero. If WriteFile() were to return at all even if it didn't make progress I'd be able to knock the thing out of its wedged state. I also don't think the log state is consistent with WriteFile() returning.
So onto ReadFile(): this is the calling sequence:
SOCKET conn;
HANDLE unwedgeEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
HANDLE listenEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
if (listenEvent == NULL) return;
//...
conn = accept(lstn);
for (;;) {
HANDLE wakeup[2];
wakeup[0] = unwedgeEvent;
wakeup[1] = listenEvent;
if (WSAEventSelect(conn, socket, FD_READ | FD_CLOSE) == 0) {
// Log error
break;
}
which = WaitForMultipleObjects(2, wakeup, FALSE, INFINITE);
if (which < 0) {
// Log error
break;
}
if (which == 1) {
DWORD read;
r = ReadFile(conn, chunk, 4096, &read, NULL);
if (r == 0) {
// Handle error -- not stuck here
} else {
// Handle data -- not stuck here either
}
}
if (which == 0) break;
}
Where signalling unwedgeEvent doesn't manage to accomplish anything and the thread remains stuck forever.
So the real question is have I gone nuts or is this really a thing that can happen?
So this has gone somewhat off the deep end; I don't need non-blocking sockets at all. I need a select() that takes handle arguments to things that are sockets and things that are not sockets.
The following API sequences do not hang in ReadFile:
---------------------------------------------------------------
Sender B Receiver
WSAEventSelect
* WaitForMultipeObjects
send(buffer size = 1)
ReadFile(size = 1)
WSAEventSelect
* WaitForMultipeObjects
send(buffer size = 1)
ReadFile(size = 1)
................................................................
WSAEventSelect
* WaitForMultipeObjects
send(buffer size = 2)
ReadFile(size = 1)
WaitForMultipeObjects
ReadFile(size = 1)
................................................................
WSAEventSelect
* WaitForMultipeObjects
send(buffer size = 1)
send(buffer size = 1)
ReadFile(size = 1)
WaitForMultipeObjects
ReadFile(size = 1)
................................................................
WSAEventSelect
send(buffer size = 1)
WaitForMultipeObjects
send(buffer size = 1)
ReadFile(size = 1)
WaitForMultipeObjects
ReadFile(size = 1)
................................................................
WSAEventSelect
send(buffer size = 1)
WaitForMultipeObjects
send(buffer size = 1)
ReadFile(size = 2)
* WaitForMultipeObjects
send(buffer size = 1)
ReadFile(size = 1)
................................................................
WSAEventSelect
send(buffer size = 1)
WaitForMultipeObjects
ReadFile(size = 1)
send(buffer size = 1)
WaitForMultipeObjects
ReadFile(size = 1)
I see a number of issues with your code:
You should use WSACreateEvent() and WSAWaitForMultipleEvents() instead of CreateEvent() and WaitForMultipleObjects(). Although the current implementation is that the former APIs simply map to the latter APIs, Microsoft is free to change that implementation at any time without breaking code that uses the former APIs properly.
In your call to WSAEventSelect(), socket should be listenEvent instead.
WSAEventSelect() returns SOCKET_ERROR (-1) on failure, not 0 like you have coded.
You are not calling WSAEnumNetworkEvents() at all, which you need to do in order to determine if FD_READ was the actual type of event triggered, and to clear the socket's event state and reset the event object. So, you may be acting on a stale read state, which could explain why you end up calling ReadFile() when there is actually nothing available to read.
WSAEventSelect() puts the socket into non-blocking mode (per its documentation), so it is actually not possible for ReadFile() (or any other reading function) to block on the socket. However, it could fail immediately with a WSAEWOULDBLOCK error, so make sure you are not treating that condition as a fatal error.
The WSAEventSelect() documentation does not list ReadFile() as a supported function for re-enabling events when calling WSAEnumNetworkEvents(). Although the Socket Handles documentation does say that a Winsock SOCKET can be used with non-Winsock I/O functions like ReadFile(), it recommends that a SOCKET should only be used with Winsock functions. So, you should use send()/recv() or WSASend()/WSARecv() instead of WriteFile()/ReadFile().
With that said, try something more like the following:
HANDLE unwedgeEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
if (unwedgeEvent == NULL) {
// Log error
return;
}
...
SOCKET conn = accept(lstn, NULL, NULL);
if (conn == INVALID_SOCKET) {
// Log error
return;
}
...
WSAEVENT listenEvent = WSACreateEvent();
if (listenEvent == NULL) {
// Log error
}
else if (WSAEventSelect(conn, listenEvent, FD_READ | FD_CLOSE) == SOCKET_ERROR) {
// Log error
}
else {
WSAEVENT wakeup[2];
wakeup[0] = (WSAEVENT) unwedgeEvent;
wakeup[1] = listenEvent;
char chunk[4096];
int read;
do {
DWORD which = WSAWaitForMultipleEvents(2, wakeup, FALSE, WSA_INFINITE, FALSE);
if (which == WSA_WAIT_FAILED) {
// Log error
break;
}
if (which == WSA_WAIT_EVENT_0) {
break;
}
if (which == (WSA_WAIT_EVENT_0+1)) {
WSANETWORKEVENTS events = {};
if (WSAEnumNetworkEvents(conn, listenEvent, &events) == SOCKET_ERROR) {
// Log error
break;
}
if (events.lNetworkEvents & FD_READ) {
read = recv(conn, chunk, sizeof(chunk), 0);
if (read == SOCKET_ERROR) {
if (WSAGetLastError() != WSAEWOULDBLOCK) {
// Log error
break;
}
}
else if (read == 0) {
break;
}
else {
// Handle chunk up to read number of bytes
}
}
if (events.lNetworkEvents & FD_CLOSE) {
break;
}
}
}
while (true);
WSACloseEvent(listenEvent);
}
closesocket(conn);
Currently for my college project, I am trying to implement FCFS and Priority scheduling algorithms for xv6. I am done with the priority one and now trying to make FCFS work out. The following is the modification i did to the code:
void
scheduler(void)
{
struct proc *p = 0;
struct cpu *c = mycpu();
c->proc = 0;
for(;;)
{
// Enable interrupts on this processor.
sti();
// Loop over process table looking for process to run.
acquire(&ptable.lock);
for(p = ptable.proc; p < &ptable.proc[NPROC]; p++)
{
struct proc *minP = 0;
if(p->state != RUNNABLE)
continue;
// ignore init and sh processes from FCFS
if(p->pid > 1)
{
if (minP != 0){
// here I find the process with the lowest creation time (the first one that was created)
if(p->ctime < minP->ctime)
minP = p;
}
else
minP = p;
}
// If I found the process which I created first and it is runnable I run it
//(in the real FCFS I should not check if it is runnable, but for testing purposes I have to make this control, otherwise every time I launch
// a process which does I/0 operation (every simple command) everything will be blocked
if(minP != 0 && p->state == RUNNABLE)
p = minP;
if(p != 0)
{
// Switch to chosen process. It is the process's job
// to release ptable.lock and then reacquire it
// before jumping back to us.
c->proc = p;
switchuvm(p);
p->state = RUNNING;
swtch(&(c->scheduler), p->context);
switchkvm();
// Process is done running for now.
// It should have changed its p->state before coming back.
c->proc = 0;
}
}
release(&ptable.lock);
}
}
Now, I would like to ask is that when I run two dummy process (doing with the convention, foo.c to produce children processes to do useless calculations that consume time) each producing a child, why is it that I am still able to run ps?
Technically, each of the 2 available CPUs must be occupied running the two dummy process correct?
Additionally, I set the creation time as Priority using the algoirthm i wrote for the Priority scheduling. Turns out, after creation of the two processes, I cannot run anything, meaning both the CPUs are in use right now.
I think you've made two mistakes:
the process context is inside your for loop, it should be after:
schedule()
{
// for ever
for(;;)
{
// select process to run
for(p = ptable.proc; p < &ptable.proc[NPROC]; p++)
{
...
}
// run proc
if (p != 0)
{
...
}
}
You've made a little mistake in minP selection:
if(minP != 0 && p->state == RUNNABLE)
p = minP;
should be
if(minP != 0 && minP->state == RUNNABLE)
p = minP;
but since minP's state is necessary RUNNABLE, and that you test that it's not null before running it, you could write
p = minP;
So you're corrected code could be:
void
scheduler(void)
{
struct proc *p = 0;
struct cpu *c = mycpu();
c->proc = 0;
for(;;)
{
sti();
struct proc *minP = 0;
// Loop over process table looking for process to run.
acquire(&ptable.lock);
for(p = ptable.proc; p < &ptable.proc[NPROC]; p++)
{
if(p->state != RUNNABLE)
continue;
// ignore init and sh processes from FCFS
if(p->pid > 1)
{
if (minP != 0) {
// here I find the process with the lowest creation time (the first one that was created)
if(p->ctime < minP->ctime)
minP = p;
}
else
minP = p;
}
}
p = minP;
release(&ptable.lock);
if(p != 0)
{
c->proc = p;
switchuvm(p);
p->state = RUNNING;
swtch(&(c->scheduler), p->context);
switchkvm();
c->proc = 0;
}
}
}
Hope all is going well.
I'm trying to ping STM32H743ZI NUCLEO 144 using LWIP middle-ware. Code generated by CubeMX.
Configurations:
Set the HCLK to 400 MHz
Enabled the CPU ICache and DCache (under Cortex_M7 Configuration)
Enabled MPU (Region0, Region1 & Region2)
Enabled LWIP
Selected LAN8742 as the Driver_PHY (under LwIP>Platform Settings)
DHCP disabled (IP, MASK: 255,255,255,000 , Gateway: Modem IP)
RTOS disabled
LWIP_HTTPD, LWIP_HTTPD_CGI enabled
LWIP_HTTPD_SSI enabled
LWIP_HTTPD_MAX_TAG_NAME_LEN set to 16
ICMP enabled (LWIP_BROADCAST_PING and LWIP_MULTICAST_PING in LwIP Key Options>IPMP Options).
Code Generated for Keil V5
MX_LWIP_Process added to the main function in While loop.
while(1)
{
MX_LWIP_Process();
}
I don't know how should I configure the CubeMX or change the generated code to be able to ping my board.
My_File
this will probably help you (it did for me):
Information about this issue can be found here.
https://community.st.com/s/article/FAQ-Ethernet-not-working-on-STM32H7x3
Memory buffers need to be assigned to RAM that can be accessed by the Ethernet
peripheral.
You may need to adjust the tour stack/heap size.
The default Ethernet GPIOs speed may be too low.
You may need to configure the MPU.
You may likely need to change your linker script.
On this page you will find good information:
https://github.com/MX-Master/STM32H7_Nucleo-H743ZI_Ethernet_LwIP
The HAL_Delay mentioned may not be required, though.
In the file lan8742.c (driver), I added an extra line for the LAN8742_Init function, around line 190, to set auto-negotiation:
// Link did not come up after HW reset.
pObj->IO.WriteReg(pObj->DevAddr, LAN8742_BCR, LAN8742_BCR_AUTONEGO_EN);
So that function looks like:
// Used in ethernetif.c, 363, static void low_level_init(struct netif *netif)
int32_t LAN8742_Init(lan8742_Object_t *pObj)
{
uint32_t tickstart = 0, regvalue = 0, addr = 0;
int32_t status = LAN8742_STATUS_OK;
if(pObj->Is_Initialized == 0)
{
if(pObj->IO.Init != 0)
{
/* GPIO and Clocks initialization */
pObj->IO.Init();
}
/* for later check */
pObj->DevAddr = LAN8742_MAX_DEV_ADDR + 1;
/* Get the device address from special mode register */
for(addr = 0; addr <= LAN8742_MAX_DEV_ADDR; addr ++)
{
if(pObj->IO.ReadReg(addr, LAN8742_SMR, ®value) < 0)
{
status = LAN8742_STATUS_READ_ERROR;
/* Can't read from this device address
continue with next address */
continue;
}
if((regvalue & LAN8742_SMR_PHY_ADDR) == addr)
{
pObj->DevAddr = addr;
status = LAN8742_STATUS_OK;
break;
}
}
if(pObj->DevAddr > LAN8742_MAX_DEV_ADDR)
{
status = LAN8742_STATUS_ADDRESS_ERROR;
}
/* if device address is matched */
if(status == LAN8742_STATUS_OK)
{
/* set a software reset */
if(pObj->IO.WriteReg(pObj->DevAddr, LAN8742_BCR, LAN8742_BCR_SOFT_RESET) >= 0)
{
/* get software reset status */
if(pObj->IO.ReadReg(pObj->DevAddr, LAN8742_BCR, ®value) >= 0)
{
tickstart = pObj->IO.GetTick();
/* wait until software reset is done or timeout occurred */
while(regvalue & LAN8742_BCR_SOFT_RESET)
{
if((pObj->IO.GetTick() - tickstart) <= LAN8742_SW_RESET_TO)
{
if(pObj->IO.ReadReg(pObj->DevAddr, LAN8742_BCR, ®value) < 0)
{
status = LAN8742_STATUS_READ_ERROR;
break;
}
}
else
{
status = LAN8742_STATUS_RESET_TIMEOUT;
}
}
}
else
{
status = LAN8742_STATUS_READ_ERROR;
}
}
else
{
status = LAN8742_STATUS_WRITE_ERROR;
}
}
}
// Jack 2019-03-25, Link did not come up after HW reset.
pObj->IO.WriteReg(pObj->DevAddr, LAN8742_BCR, LAN8742_BCR_AUTONEGO_EN);
if(status == LAN8742_STATUS_OK)
{
tickstart = pObj->IO.GetTick();
/* Wait for 2s to perform initialization */
while((pObj->IO.GetTick() - tickstart) <= LAN8742_INIT_TO)
{
}
pObj->Is_Initialized = 1;
}
return status;
}
I'm learning about osdev and looking up xv6 code, currently - the console code in particular. Basically, I don't get how the console launches a process.
in console.c there is a function:
void consoleintr(int (*getc)(void)) {
....
while((c = getc()) >= 0) {
switch(c) {
....
default:
....
if(c == '\n' || c == C('D') || input.rightmost == input.r + INPUT_BUF) {
wakeup(&input.r);
}
}
}
So I get it, when the line ends (or the length of the buffer exceeds maximum), it launches wakeup(&input.r)
Then there is this in proc.c:
// Wake up all processes sleeping on chan.
// The ptable lock must be held.
static void wakeup1(void *chan)
{
struct proc *p;
for(p = ptable.proc; p < &ptable.proc[NPROC]; p++)
if(p->state == SLEEPING && p->chan == chan)
p->state = RUNNABLE;
}
// Wake up all processes sleeping on chan.
void wakeup(void *chan)
{
acquire(&ptable.lock);
wakeup1(chan);
release(&ptable.lock);
}
What is happening here? Why is it comparing address of a console buffer and proc's chan? What is this chan?
It is for processes who waiting (sleeps) for console input. See here:
235 int
236 consoleread(struct inode *ip, char *dst, int n)
...
251 sleep(&input.r, &cons.lock);
The code you have mentioned wakeups this sleeping processes, because data have came from console and is available now for processing.
chan - is a channel. You can wait (sleep) for different things. This channel is for console input data.
I am working on STM32F4 board. My IDE is IAR Embedded Work bench. I am trying to do a software reset from code. For that i used API ' NVIC_SystemReset(); ' defined in
core_cm4.h header. But the system reset is not happening.
I tried the same thing in STM32F3, same IDE . I used the function NVIC_SystemReset(); from core_sc300.h header. Using that software reset is happening. I found the definition of functions in both file are same and both controllers are Cortex M4 only.What is the problem with STM32F4 board.? Can any one help me in solving this or can any one suggest an alternative way for system reset in STM32F4.
Please help.
Thanks in advance
In the HAL You can use
HAL_NVIC_SystemReset();
You can use a watch-dog instead:
Call wdg_activate(n) in order to initiate system-reset within n milliseconds
Call wdg_reactivate() in order to reload the counter back to n milliseconds
void wdg_activate(unsigned short num_of_ms)
{
uint8_t prescale_reg;
uint8_t prescale_val;
if (num_of_ms < 1)
{
num_of_ms = 1;
prescale_reg = IWDG_Prescaler_32;
prescale_val = 1;
}
else if (num_of_ms <= 4096)
{
prescale_reg = IWDG_Prescaler_32;
prescale_val = 1;
}
else if (num_of_ms <= 8192)
{
prescale_reg = IWDG_Prescaler_64;
prescale_val = 2;
}
else if (num_of_ms <= 16384)
{
prescale_reg = IWDG_Prescaler_128;
prescale_val = 4;
}
else if (num_of_ms <= 32768)
{
prescale_reg = IWDG_Prescaler_256;
prescale_val = 8;
}
else
{
num_of_ms = 32768;
prescale_reg = IWDG_Prescaler_256;
prescale_val = 8;
}
IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable);
while (IWDG_GetFlagStatus(IWDG_FLAG_PVU));
IWDG_SetPrescaler(prescale_reg);
while (IWDG_GetFlagStatus(IWDG_FLAG_RVU));
IWDG_SetReload(num_of_ms/prescale_val-1);
IWDG_Enable();
}
void wdg_reactivate()
{
IWDG_ReloadCounter();
}
There have been several iterations of NVIC_SystemReset(). Please post the code for the version you are using. The current [working STM32F4] version that I am using is as follows:
/** \brief System Reset
The function initiates a system reset request to reset the MCU.
*/
__STATIC_INLINE void NVIC_SystemReset(void)
{
__DSB(); /* Ensure all outstanding memory accesses included
buffered write are completed before reset */
SCB->AIRCR = ((0x5FA << SCB_AIRCR_VECTKEY_Pos) |
(SCB->AIRCR & SCB_AIRCR_PRIGROUP_Msk) |
SCB_AIRCR_SYSRESETREQ_Msk); /* Keep priority group unchanged */
__DSB(); /* Ensure completion of memory access */
while(1); /* wait until reset */
}