MC68HC05P4A Datasheet, PDF (34/72 Pages) Advanced Analogic Technologies – Microcontrollers

Simple Serial Input/Output Port (SIOP)
7.3.3 SIOP Data Register
This register is located at address $000C and is both the transmit and receive data register. This system
is not double buffered and any write to this register will destroy the previous contents. The SDR can be
read at any time, but if a transmission is in progress the results may be ambiguous. Writes to the SDR
while a transmission is in progress can cause invalid data to be transmitted and/or received. This register
can be read and written only when the SIOP is enabled (SPE = 1).
Address: $000C
Bit 7
6
5
4
3
2
1
Bit 0
Read:
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Write:
Reset:
Unaffected by reset
Figure 7-5. SIOP Data Register (SDR)
MC68HC05P4A Data Sheet, Rev. 7.1
34
Freescale Semiconductor