Part Number: TL16C754C
Other Parts Discussed in Thread: MAX3243, TM4C1294KCPDT, TL16C554A
Hi,
I am using the TL16C754CPM device, where its Channels A & B are going out to a DB9 connector (through a MAX3243), Channels C & D are going to two UART channels of the TI TM4C1294KCPDT Serial to Ethernet device. The 16C754 device is controlled by a PIC16F887 device.
After repeated efforts in trying to resolve the error issues, to keep the set up as simple as possible, I have it now such that data is received on Channel B and sent out on Channel A.
Channels A & B are connected directly to the serial ports on 2 different computers.
I am using only the POLLED mode without any Interrupts.
The PIC is having an instruction cycle time of 325ns (12.288MHz) and the 16C754 is using a 6.144MHz crystal.
HyperTerminal is running on both computers, both computers and both Channels A & B set to the same baud rate, parity, stop bits etc.
I send data from PC-1 to Channel B, the PIC reads from Channel B and writes in to Channel A, which is received by PC-2 and displayed on the HyperTerminal screen.
When we manually type the data - keep a key pressed for continuous repeated sending of the same key - we do not face any errors at any baud rate or parity / 7 or 8 bits / stop bit combinations.
Whatever is typed on PC-1 appears on PC-2 without any errors.
But, when we use a program to send a line of characters (max 30), then the problem starts.
Errors start appearing at 300,N,8,1,whereas 1200,N,8,1 up to 19200,N,8,1 works without any errors. (We only need from 300 to 19200)
Errors appear at any baud rate when using 7 bits and Odd or Even parity.
The setting of the DLL / DLH / LCR are correct, verified by reading all the registers.
Whether the RX FIFO is disabled or Enabled with trigger level at any of the 4 settings, the result is the same.
Option 1 was to read from Channel B, write into Channel A, byte by byte - same result as above
Option 2 was to read from Channel B, store in memory, until a time out (no data) for about 0.5 sec and then read from memory and send these characters out on Channel A - same result as above.
Replaced the TL16C754CPM device - same result. These TL16C754CPM devices were received as samples directly from TI.
So, what else information do you need from me ?
How or where do I look for a problem ?
Character by character with manual typing does not give any problem - so, there is no error in setting the registers of the device or read / write.
But when characters are sent continuously by a program, there seems to be some timing issue.
HELP !
