Sundance SMT118 - Manual (Page 9)

Version 1.0 Page 9 of 20 SMT118v2 User Manual
LEDs
Four LEDs are provided on the SMT118. These can be illuminated under application
control by writing to the register at address 0xFB000000. Bits 0 to 3 of this register
correspond to the on-board LEDs. Setting a bit to a logic 1 will illuminate the LED.
Another 4 off-board LED signals are provided. These are available on the CONN8
connector. Each of the four bits is controlled directly by the state of bits 4 to 7 of the
above register. Setting a bit to logic 1 will output a high LVTTL signal. i.e. if they are
intended to drive LEDs, then these outputs should be wired via a suitable (220Ohm
min) series resistor, to the anode of the LED. The LED’s cathode should then be
connected to ground.
QUART
The quad UART employed is an Oxford Semiconductor 16C954. It generates TXD,
RTS and DTR. It receives RXD, CTS, DSR, DCD and RI. All of these connections are
translated to true RS-232 levels and then connected to 10 pin IDC headers (CONN4
to 7) for direct connection of a standard PC pin-out 9-way D-type connector.
The UARTs within this device occupy 8 registers addresses. The base address for
the QUART is 0xF9000000, this being the base address for UART1 also.
Subsequent base addresses for the UARTs 2, 3 and 4 are 0xF9000008, 0xF9000010
and 0xF9000018 respectively.
The single QUART interrupt is connected to the FPGA and can be used to generate
a CPU interrupt.