HD64570 HITACHI [Hitachi Semiconductor], HD64570 Datasheet - Page 73

• Manufacturer Part Number: HD64570
• Description: Serial Communications Adaptor
• Manufacturer: HITACHI [Hitachi Semiconductor]

Bits 7 1: Reserved. These bits always read 0 and must be set to 0.
Bit 0 (IOSTP: I/O Stop): Controls transition to low-power mode (system stop mode).
IOSTP = 0: The SCA remains in its current operating mode and does not enter system stop mode.
IOSTP = 1:
mode, so once it is set to 1 to enter system stop mode, the IOSTP bit cannot be cleared to 0 except
by a reset. Figure 3.3 shows transition timing in system stop mode.
Read/Write
Initial value
Note: Bit 7–bit 1 are reserved. These bits always read 0 and must be set to 0.
Bit name
The SCA enters system stop mode. Registers cannot be written or read in this
—
—
7
0
—
—
6
0
—
—
I/O stop
0:
1:
5
0
No transition to system stop mode
Transition to system stop mode
—
—
4
0
—
—
3
0
—
—
2
0
Rev. 0, 07/98, page 57 of 453
—
—
1
0
IOSTP
R/W
0
0