State Machine - |ex10|spi2dac:s|sr_state
Name sr_state.IDLE sr_state.WAIT_CSB_HIGH sr_state.WAIT_CSB_FALL 
sr_state.IDLE 0 0 0 
sr_state.WAIT_CSB_FALL 1 0 1 
sr_state.WAIT_CSB_HIGH 1 1 0