Hi,
I think I found a memory overwrite issue, and would like to confirm my understanding of what is going on.
I have found something out about the automatic DMA buffer, and I would like to confirm my understanding. I had tried IN_BUFFER[8] and OUT_BUFFER[8],
and my program wasn't working correctly. A counting variable kept getting overridden at approximately the ### location. I then changed to IN_BUFFER[32] and OUT_BUFFER[32].
With these new buffer lengths the issue was resolved. Please see https://www.cypress.com/file/376416/download pg 63.
"The DMA reading from or writing into the endpoint buffer happens in 32 byte chunks per request".
I contrast that with the code definition of ReadOutEp: "Valid values are between 0 and 1023", in which it speaks about the third parameter.
I think that I was overriding the other variables, because my buffer sizes were too small. Can I get a confirmation of this please?
#include "project.h"
#include <stdio.h>
#define IN_ENDPOINT 0x01
#define OUT_ENDPOINT 0x02
#define MAX_NUM_BYTES 1
#define PACKET_OK 1
#define PACKET_BAD 0
#define maxLength 19 // 20 long -> array element 19
// These are for the keypads
#define Pin_DM_STRONG (0x06u)
#define Pin_DM_RES_UP (0x02u)
uint8 IN_Data_Buffer[8] = {0};
uint8 OUT_Data_Buffer[8] = {0} ;
uint8 PacketNum = 0;
uint8 packetOk = 0;
char textIn[20];
char textOut[20];
uint8 textInLength = 0;
uint8 textInIndex = 0;
uint8 textOutLength = 0;
uint8 textOutIndex = 0;
int main(void)
{
CyGlobalIntEnable; /* Enable global interrupts. */
// Start the Screen
LCD_Start();
Timer_Start();
keyTimer_Start();
LCD_ISR_StartEx(LCD_Interrupt);
keyISR_StartEx(Keypad_ISR);
/* Place your initialization/startup code here (e.g. MyInst_Start()) */
USB_Start(0,USB_DWR_VDDD_OPERATION);
#define UnassignedAddress 0
while(USB_deviceAddress == UnassignedAddress)
{
// Wait for device address to be assigned
}
while(!(USB_GetConfiguration()));
for(;;)
{
uint8 interruptState;
interruptState = CyEnterCriticalSection();
/* Place your application code here. */
// the primary USB send and receive function
OUT_COUNT = 0;
// ensure that device is configured
//if(USB_bGetConfiguration() )
//{
if(USB_IsConfigurationChanged()) //make happen every time
{
//USB_GetInterfaceSetting(0); // works without this line???
USB_LoadEP(IN_ENDPOINT, IN_Data_Buffer, 8);
USB_ReadOutEP(OUT_ENDPOINT, OUT_Data_Buffer, OUT_COUNT);
USB_EnableOutEP(OUT_ENDPOINT);
}
//CyDelay(1);
//############################################################################################################
if ((USB_GetEPState(IN_ENDPOINT) == USB_IN_BUFFER_EMPTY ) ) //Data to send
{
USB_LoadEP(IN_ENDPOINT, NULL, 8);
//USB_EnableOutEP(OUT_ENDPOINT);
}
//CyDelay(1);
if(USB_GetEPState(OUT_ENDPOINT) == USB_OUT_BUFFER_FULL) /// Data to Receive
{
//############################################################################################################
OUT_COUNT = USB_GetEPCount(OUT_ENDPOINT);
USB_EnableOutEP(OUT_ENDPOINT);
}
//}
if (OUT_COUNT != 0)
{
char tempChar = (char)OUT_Data_Buffer[0];
// this loop resets the OUT line on LCD
// once it is full and more text has arrived
if(textOutLength > maxLength)
{
textOutLength = 0;
//LCD_Position(1u,0u);
// this loop blanks the OUT line on LCD
// it is 21 elements long, even though the screen is 20
// b/c I append a \0 when sending the text from PC
for(int z = 0; z <= 20; z++)
{
textOut = ' ';
}
int bob = 0;
}
if (tempChar != 0)
{
textOut[textOutLength] = tempChar;
textOutLength = textOutLength + 1;
IN_Data_Buffer[0] = OUT_Data_Buffer[0];
if(textInLength > maxLength)
{
textInLength = 0;
textInIndex = 0; // should I update this one here???
for(int i = 0; i < 20; i++)
{
textIn = ' ';
}
}
textIn[textInLength] = IN_Data_Buffer[0];
textInLength = textInLength + 1;
}
}
CyExitCriticalSection(interruptState);
}
}
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Nov 10, 2020
Solved
