pcm-02.py

# Set the EN bit to enable the PCM block. 
mem32[CS_A] = 1
# Set all operational values to define the frame and channel settings. 
mem32[MODE_A] = 1<<24 | 1<<22 | 1<<20 | 31<<10 | 16
mem32[TXC_A]  = 1<<30 | 1<<20 | (16-8)<<16 | 1<<14 | 17<<4 | (16-8)
# Assert RXCLR and/or TXCLR wait for 2 PCM clocks to ensure the FIFOs are reset. 
mem32[CS_A] |= 1<<4 | 1<<3
# The SYNC bit can be used to determine when 2 clocks have passed.
mem32[CS_A] |= 1<<24
while (mem32[CS_A] & 1<<24) == 0:
  pass
# Set RXTHR/TXTHR to determine the FIFO thresholds.
mem32[CS_A] |= 3<<5
# If transmitting, ensure that sufficient sample words have been written to PCMFIFO
# before transmission is started. 
for i in range(32):
  mem32[FIFO_A] = 0