26
- bit 0 of the MCR register = 0 means RS485 line receiving
- bit 0 of the MCR register = 1 means RS485 line transmitting
The I/O address of the MCR is "Serial port Base address"+4H.
See Chapter 4 for info about the Serial ports configuration.
J7 for 2 x USB, J8 for AUDIO-CODEC
J7 for 2 x USB
J7 is a double row 4 x 2 pin with 2.00-mm step connector.
2 x USB
Figure 13. J7 Connector layout
Two USB ports are provided on the SpacePC 1232 module for the connection of USB devices.
Table 11.
J7 2 x USB connector
Pin
Signal
Function
1
PE
USB power enable
2
OC
USB over current sense
3
USB1N
USB port 1 differential line (minus line)
4
USB2N
USB port 2 differential line (minus line)
5
USB1P
USB port 1 differential line (plus line)
6
USB2P
USB port 2 differential line (plus line)
7
GND
Ground signal
8
GND
Ground signal
All the timers have the same input clocks with a nominal frequency of 1MHz.
All the gate inputs are pulled high by a 4.7K resistor