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8XC196NT USER’S MANUAL
8-6
Figure 8-3. SSIO Transmit/Receive Timings
8.4
SSIO HANDSHAKING
Handshaking (Figure 8-4) prevents a data underflow or overflow from occurring at the slave,
which enables a master device to perform SSIO data transfers using the PTS. Without handshak-
ing, data overflows and underflows would make it nearly impossible to use the PTS for transfer-
ring blocks of data. Handshaking takes place in hardware, using the clock pins, with no CPU
overhead. When the master is the transmitter and the slave is the receiver, the slave pulls the clock
line low until it is ready to receive a byte. This prevents a data overflow at the slave. In the oppo-
site configuration, the slave pulls the clock line low until its buffer is loaded with data. This pre-
vents a data underflow at the slave.
8.4.1
SSIO Handshaking Configuration
To use the PTS with the SSIO in handshaking mode, the SSIO channels must be configured as
follows:
•
Channels must be auto-enabled (both the ATR and STE bits in SSIOx_CON must be set).
•
Handshaking mode must be selected (the THS bit in SSIOx_CON must be set).
•
The clock pin, SCx, must be configured as a special-function, open-drain output in both
master and slave. (This requires an external pull-up resistor.)
MSB
D6
D5
D4
D3
D2
D1
D0
valid
valid
valid
valid
valid
valid
valid
valid
1
8
7
6
5
4
3
2
1
8
7
6
5
4
3
2
STE
SC
x
SD
x
(out)
SD
x
(in)
SC
x
(Handshake Mode)
Slave Receiver Pulls SC
x
low
A0266-01
Содержание 8XC196NT
Страница 1: ...8XC196NT Microcontroller User s Manual...
Страница 2: ...8XC196NT Microcontroller User s Manual June 1995 Order Number 272317 003...
Страница 22: ...1 Guide to This Manual...
Страница 23: ......
Страница 35: ......
Страница 36: ...2 Architectural Overview...
Страница 37: ......
Страница 49: ......
Страница 50: ...3 Programming Considerations...
Страница 51: ......
Страница 66: ...4 Memory Partitions...
Страница 67: ......
Страница 104: ...5 Standard and PTS Interrupts...
Страница 105: ......
Страница 147: ......
Страница 148: ...6 I O Ports...
Страница 149: ......
Страница 176: ...7 Serial I O SIO Port...
Страница 177: ......
Страница 194: ...8 Synchronous Serial I O SSIO Port...
Страница 195: ......
Страница 211: ......
Страница 212: ...9 Slave Port...
Страница 213: ......
Страница 231: ......
Страница 232: ...10 Event Processor Array EPA...
Страница 233: ......
Страница 270: ...11 Analog to digital Converter...
Страница 271: ......
Страница 291: ......
Страница 292: ...12 Minimum Hardware Considerations...
Страница 293: ......
Страница 306: ...13 Special Operating Modes...
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Страница 317: ......
Страница 318: ...14 Interfacing with External Memory...
Страница 319: ......
Страница 362: ...15 Programming the Nonvolatile Memory...
Страница 363: ......
Страница 408: ...A Instruction Set Reference...
Страница 409: ......
Страница 476: ...B Signal Descriptions...
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Страница 493: ......
Страница 494: ...C Registers...
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Страница 565: ......
Страница 566: ...Glossary...
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Страница 580: ...Index...
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