User Uart - Fujitsu DevKit16 User Manual

Output mode
Read: The level at the corresponding pin is read. In most cases it will be the
value written to the pin as last, the only exception can happen when the
pin is erroneously pulled hard to VCC or GND.
Write: Data is written to an output latch and output to the corresponding pin.
(2) Port direction registers
DDR4 7
Address: E4 D07 D06
H
DDR5 15
Address: E5 D17 D16
H
DDR6 7
Address:E6 D27 D26
H
DDR7 15
Address:+E7 D37 D36
H
When reading the register, last value written to it is returned.
Pins are controlled as described below:
0: Input mode
1: Output mode
Note: The port direction registers are WRITE ONLY. Pull-up resistors
47K are internally connected to port pins.
U S E R U A R T
The User UART has the "mimic" of a simplified 16550C serial
asynchronous UART. The main differences are:
• received and transmitted data are double buffered, not FIFOed in 16
bytes long buffer
• only basic serial stream mode is provided (1 start, 8 data bits, 1 stop bit)
• Send Break and Break Indicate functions supported
• the number of baud rates is limited to 16
• Hardware flow control CTS, RTS signals are used by default
• no DSR, DTR signals
6 5 4 3
D05 D04 D03
14 13 12 11
D15 D14 D13
6 5 4 3
D25 D24 D23
14 13 12 11
D35 D34 D33
65 65
65 65
2 1 0 Initial
value
D02 D01 D00 00
10 9 8 Initial
value
D12 D11 D10 00
2 1 0 Initial
value
D22 D21 D20 00
10 9 8 Initial
value
D32 D31 D30 00
Access
W
H
Access
W
H
Access
W
H
Access
W
H