Intel 386 - Manual (Page 423)

Intel386™ EX EMBEDDED MICROPROCESSOR USER’S MANUAL
13-24
13.3.8 SSIO Transmit Holding Buffer (SSIOTBUF)
Write the data words to be transmitted to SSIOTBUF. Use the interrupt controller, DMA unit or
polling (read SSIOCON1) to determine when to write to the transmit buffer.
Figure 13-22. SSIO Transmit Holding Buffer (SSIOTBUF)
Transmit Holding Buffer
SSIOTBUF
(read/write) Expanded Addr:
ISA Addr:
Reset State: F480H
—
0000H
15 8
TB15 TB14 TB13 TB12 TB11 TB10 TB9 TB8
7 0
TB7 TB6 TB5 TB4 TB3 TB2 TB1 TB0
Bit
Number
Bit
Mnemonic
Function
15–0 TB15:0 Transmit Buffer Bits:
These bits make up the next data word to be transmitted. The control
logic loads this word into the transmit shift register. The transmit shift
register shifts the bits out on the falling edge of the tranmitter clock pin.
The word is transmitted out starting with the most-significant bit (TB15).