PC912XDP512F0CFVR datasheet(492/1348 Pages) FREESCALE

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Chapter 11 Serial Communication Interface (S12SCIV5)

MC9S12XDP512 Data Sheet, Rev. 2.21

492

Freescale Semiconductor

11.3.2.9

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.

76543210

RR8

000000

Reset

00000000

= Unimplemented or Reserved

Figure 11-12. SCI Data Registers (SCIDRH)

76543210

R7R6R5R4R3R2R1R0

Reset

00000000

Figure 11-13. SCI Data Registers (SCIDRL)

Table 11-12. SCIDRH and SCIDRL Field Descriptions

Field

Description

SCIDRH

Received Bit 8 — R8 is the ninth data bit received when the SCI is conﬁgured for 9-bit data format (M = 1).

SCIDRH

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

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