Chapter 15 Serial Communication Interface (S12MC9S12XDP512V5)
MC9S12XDP512 Data Sheet, Rev. 2.11
Freescale Semiconductor 687
15.3.2.9 SCI Data Registers (SCIDRH, SCIDRL)
Read: Anytime; reading accesses SCI receive data register
Write: Anytime; writing accesses SCI transmit data register; writing to R8 has no effect
NOTE
If the value of T8 is the same as in the previous transmission, T8 does not
have to be rewritten.The same value is transmitted until T8 is rewritten
In 8-bit data format, only SCI data register low (SCIDRL) needs to be
accessed.
When transmitting in 9-bit data format and using 8-bit write instructions,
write first to SCI data register high (SCIDRH), then SCIDRL.
Module Base + 0x0006
76543210
RR8 T8 000000
W
Reset 00000000
= Unimplemented or Reserved
Figure 15-12. SCI Data Registers (SCIDRH)
Module Base + 0x0007
76543210
RR7R6R5R4R3R2R1R0
WT7 T6 T5 T4 T3 T2 T1 T0
Reset 00000000
Figure 15-13. SCI Data Registers (SCIDRL)
Table 15-13. SCIDRH and SCIDRL Field Descriptions
Field Description
SCIDRH
7
R8
Received Bit 8 — R8 is the ninth data bit received when the SCI is configured for 9-bit data format (M = 1).
SCIDRH
6
T8
Transmit Bit 8 — T8 is the ninth data bit transmitted when the SCI is configured for 9-bit data format (M = 1).
SCIDRL
7:0
R[7:0]
T[7:0]
R7:R0 — Received bits seven through zero for 9-bit or 8-bit data formats
T7:T0 — Transmit bits seven through zero for 9-bit or 8-bit formats