[email protected] wrote: > As discussed on IRC, glitches can easily wreck the current clock > recovery system. I'll try adding a deglitching circuit on the input > signal path in the FPGA.
Here's more information on the errors: I finally succeded in upgrading to the 8k SoC+BIOS, and was promptly greeted by an endless stream of complaints about IN responses from my full-speed keyboard. In a run of 151 seconds, softusb reported a total of 3877 unwelcome patterns. That's about 25 per second or 2.5% of all IN packets. The corruption rate was as follows: Pattern Frequency ------- --------- 0xb6 2242 0xda 1580 0xba 55 It also reported a CC 5A once. Here's what the patterns look like NRZI-encoded, compared to IN (0x5a): Byte Bits (LSB->MSB) D+ ------- --------------- --------- IN 5a 0101 1010 _--___--_ b6 0110 1101 _---___-- Byte Bits (LSB->MSB) D+ ------- --------------- --------- IN 5a 0101 1010 _--___--_ da 0101 1011 _--___--- Byte Bits (LSB->MSB) D+ ------- --------------- --------- IN 5a 0101 1010 _--___--_ ba 0101 1101 _--____-- So it does indeed seem that the sample clock is running a bit fast for some reason. - Werner _______________________________________________ http://lists.milkymist.org/listinfo.cgi/devel-milkymist.org IRC: #milkymist@Freenode
