Datasheet

Chapter 8 Serial Communication Interface (SCIV3)
MC9S12E128 Data Sheet, Rev. 1.07
Freescale Semiconductor 257
8.3.2.6 SCI Data Registers (SCIDRH and 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 to SCIDRL.
76543210
RR8
T8
000000
W
Reset 0 0 0 00000
= Unimplemented or Reserved
Figure 8-9. SCI Data Register High (SCIDRH)
Table 8-9. SCIDRH Field Descriptions
Field Description
7
R8
Received Bit 8 — R8 is the ninth data bit received when the SCI is configured for 9-bit data format (M = 1).
6
T8
Transmit Bit 8 — T8 is the ninth data bit transmitted when the SCI is configured for 9-bit data format (M = 1).
76543210
RR7R6R5R4R3R2R1R0
W T7 T6 T5 T4 T3 T2 T1 T0
Reset 0 0 0 00000
Figure 8-10. SCI Data Register Low (SCIDRL)
Table 8-10. SCIDRL Field Descriptions
Field Description
7:0
R[7:0]
T[7:0}
Received bits 7 through 0 — For 9-bit or 8-bit data formats
Transmit bits 7 through 0 — For 9-bit or 8-bit formats