Serial Control Register - Hitachi SH7032 Hardware Manual

• Bits 1 and 0 (Clock Select 1 and 0 (CKS1 and CKS0)): CKS1 and CKS0 select the internal
clock source of the on-chip baud rate generator. Four clock sources are available: φ, φ/4, φ/16,
and φ/64. For further information on the clock source, bit rate register settings, and baud rate,
see section 13.2.8, Bit Rate Register (BRR).
Bit 1: CKS1 Bit 0: CKS0
0 0
1
1 0
1
13.2.6

Serial Control Register

The serial control register (SCR) enables the SCI transmitter/receiver, selects serial clock output in
asynchronous mode, enables and disables interrupts, and selects the transmit/receive clock source.
The CPU can always read and write to SCR. SCR is initialized to H'00 by a reset and in standby
mode.
Bit:
Bit name:
Initial value:
R/W:
• Bit 7 (Transmit Interrupt Enable (TIE)): TIE enables or disables the transmit-data-empty
interrupt (TXI) requested when the transmit data register empty bit (TDRE) in the serial status
register (SSR) is set to 1 due to transfer of serial transmit data from TDR to TSR.
Bit 7: TIE
0
1
356
Description
System clock (φ)
φ/4
φ/16
φ/64
7 6
TIE RIE TE
0 0
R/W R/W R/W
Description
Transmit-data-empty interrupt request (TXI) is disabled
The TXI interrupt request can be cleared by reading TDRE after it has
been set to 1, then clearing TDRE to 0, or by clearing TIE to 0.
Transmit-data-empty interrupt request (TXI) is enabled
5 4 3
RE MPIE
0 0 0
R/W R/W
(Initial value)
2 1
TEIE CKE1 CKE0
0 0
R/W R/W R/W
(Initial value)
0
0