MC68HC05JJ6 Datasheet, PDF (93/216 Pages) Freescale Semiconductor, Inc – General Release Specification Microcontrollers

Parallel Input/Output
When using the PB5/SDO pin, these interactions must be noted:
1. If the SIOP function is required, then the SPE bit in the SCR must
be set. This causes the PB5/SDO pin buffer to be enabled and to
be driven by the serial data output (SDO) from the SIOP. The
pulldown device will be disabled in this case.
2. If the SIOP function is in control of the PB5/SDO pin, the DDRB5
and PB5 data register bits are still accessible to the CPU and can
be altered or read without affecting the SIOP functionality.
However, if the DDRB5 bit is cleared, reading the PB5 data
register will return the current state of the PB5/SDO pin.
3. If the SIOP function is terminated by clearing the SPE bit in the
SCR, then the last conditions stored in the DDRB5, PDIB5, and
PB5 register bits will then control the PB5/SDO pin.
4. If the PB5/SDO pin is to be a digital input, then both the SPE bit in
the SCR and the DDRB5 bit must be cleared. Depending on the
external application, the pulldown device may also be disabled by
setting the PDIB5 pulldown inhibit bit.
5. If the PB5/SDO pin is to be a digital output, then the SPE bit in the
SCR must be cleared and the PDIB5 bit must be set. The pulldown
device will be disabled in this case.
MC68HC05JJ6/MC68HC05JP6 — Rev. 3.2
Freescale Semiconductor
Parallel Input/Output
General Release Specification
93