06-12-2017, 01:44 PM
Some people have run into problems with CometChat hanging when using WiModem at 38k. I did some troubleshooting this weekend and think I've root-caused it to the WiModem.
When using 38K, sequences of characters longer than 128 sent in close proximity seem to be getting truncated. This even occurs without screen-blanking. enabled, which means that communication only occurs while the scanline is in the vertical border.
If I had to speculate (and I know... I don't, but I can't help it... :p) ... I'd say there is a 128-byte buffer for receiving from the C64, and the packetization parameters are not tuned well, maybe a watermark needs to be reduced. I'm kinda surprised that it happens with screen-blanking disabled, because in that mode only about 11 bytes may be transferred per VIC frame, with over 13 milliseconds between each group of 11.
I've only tested this with a program that generates one chat-oriented burst of bytes at a time, and not with the SAVE command, but I'm 99.9% sure that saves will be broken too. I'll try to test that and post the results.
Let me know if you'd like me to share my test code.
// Agent Friday
When using 38K, sequences of characters longer than 128 sent in close proximity seem to be getting truncated. This even occurs without screen-blanking. enabled, which means that communication only occurs while the scanline is in the vertical border.
If I had to speculate (and I know... I don't, but I can't help it... :p) ... I'd say there is a 128-byte buffer for receiving from the C64, and the packetization parameters are not tuned well, maybe a watermark needs to be reduced. I'm kinda surprised that it happens with screen-blanking disabled, because in that mode only about 11 bytes may be transferred per VIC frame, with over 13 milliseconds between each group of 11.
I've only tested this with a program that generates one chat-oriented burst of bytes at a time, and not with the SAVE command, but I'm 99.9% sure that saves will be broken too. I'll try to test that and post the results.
Let me know if you'd like me to share my test code.
// Agent Friday