![NEC V854 UPD703006 Скачать руководство пользователя страница 225](http://html.mh-extra.com/html/nec/v854-upd703006/v854-upd703006_user-manual_249287225.webp)
User’s Manual U11969EJ3V0UM00
225
CHAPTER 8 SERIAL INTERFACE FUNCTION
(2) Enabling transmission/reception
Each CSIn has only one 8-bit shift register and does not have a buffer. Transmission and reception are
therefore performed simultaneously.
(a) Transmission/reception enabling condition
The transmission/reception enabling condition of CSIn is specified by the CTXEn and CRXEn bits of the
CSIMn register.
CTXEn
CRXEn
Transmission/Reception Operation
0
0
Transmission/reception disabled
0
1
Reception enabled
1
0
Transmission enabled
1
1
Transmission/reception enabled
Remark
n = 0 to 3
Remarks
1. When CTXEn bit is 0, SOn pin output of CSIn becomes high impedance.
When CTXEn bit is 1, the data of the SIOn register of CSIn is output.
2. When CRXEn bit = 0, the shift register input is “0”.
When CRXEn bit = 1, the serial input data is input to the shift register.
3. To receive the transmit data and to check whether bus contention occurs, set CTXEn bit and
CRXEn bit to 1.
(b) Starting transmission/reception
Transmission/reception is started by reading/writing the SIOn registers. Transmission/reception is
controlled by setting the transmission enable bit (CTXEn) and reception enable bit (CRXEn) as follows:
CTXEn
CRXEn
Start Condition
0
0
Does not start
0
1
Reads SIOn registers
1
0
Writes SIOn registers
1
1
Writes SIOn registers
0
0
→
1
Rewrites CRXEn bits
Remark
n = 0 to 3
In the above table, note that these bits should be set in advance of data transfer. For example,
if the CTXEn bit is not changed from 0 to 1 before reading data from or writing data to the SIOn registers,
transfer will not begin. The bottom of the table means that, if the CRXEn bit is changed from 0 to 1
when the CTXEn bit is “0”, the serial clock will be generated to initiate receive operation.
Содержание V854 UPD703006
Страница 2: ...2 User s Manual U11969EJ3V0UM00 MEMO ...
Страница 22: ...22 User s Manual U11969EJ3V0UM00 MEMO ...
Страница 80: ...80 User s Manual U11969EJ3V0UM00 MEMO ...
Страница 134: ...134 User s Manual U11969EJ3V0UM00 MEMO ...
Страница 156: ...156 User s Manual U11969EJ3V0UM00 MEMO ...
Страница 294: ...294 User s Manual U11969EJ3V0UM00 MEMO ...
Страница 320: ...320 User s Manual U11969EJ3V0UM00 MEMO ...
Страница 324: ...324 User s Manual U11969EJ3V0UM00 MEMO ...
Страница 336: ...336 User s Manual U11969EJ3V0UM00 MEMO ...
Страница 376: ...376 User s Manual U11969EJ3V0UM00 MEMO ...
Страница 382: ...382 User s Manual U11969EJ3V0UM00 MEMO ...
Страница 394: ...394 User s Manual U11969EJ3V0UM00 MEMO ...
Страница 396: ...396 User s Manual U11969EJ3V0UM00 MEMO ...