Format Of Serial Trigger Register 0 (Csit0) - NEC 78K0 User Manual

(3) Serial trigger register 0 (CSIT0)
This is an 8-bit register used to control execution/stop of automatic data transfer between buffer RAM and
serial I/O shift register 0 (SIOA0).
This register can be set by a 1-bit or 8-bit memory manipulation instruction.
RESET input clears this register to 00H. However, manipulate only when bit 6 (ATE0) of serial operation
mode specification register 0 (CSIMA0) is 1 (manipulation prohibited when ATE0 = 0).
Address: FF92H After reset: 00H
Symbol 7
CSIT0
0
ATSTP0
0
1
Automatic data transfer stopped
ATSTA0
0
1
Automatic data transfer started
Cautions 1. Even if ATSTP0 or ATSTA0 is set to 1, automatic transfer cannot be started/stopped until 1-
byte transfer is complete.
2. ATSTP0 and ATSTA0 change to 0 automatically after the interrupt signal INTACSI is
generated.
3. After automatic data transfer is stopped, the data address when the transfer stopped is
stored in automatic data transfer address count register 0 (ADTC0). However, since no
function to restart automatic data transfer is incorporated, when transfer is stopped by
setting ATSTP0 = 1, start automatic data transfer by ATSTA0 after re-setting the registers.
CHAPTER 17 SERIAL INTERFACE CSIA0
Figure 17-5. Format of Serial Trigger Register 0 (CSIT0)
R/W
6 5
0 0
*
User's Manual U15947EJ2V0UD
4 3 2
0 0 0
Automatic data transfer stop
−
Automatic data transfer start
−
<1> <0>
ATSTP0 ATSTA0
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