Knowledge Base

Push the 1st character in the Rx buffer for the serial port at address pp into X, delete it from buffer. R register signals outcome. 0 = OK, 1 = buffer was empty.

This differs from the same instruction without the leading ‘a’ in that it explicitly nominates a serial port address (pp) rather than the default serial port.

Dialect exclusions: Not available in dialects before 29

Can only exist on boards that have an uncommitted serial port other than the programming port.