Elan Digital Systems Ltd.
2
HD717 USER’S
GUIDE
CONTENTS
1. OVERVIEW..................................................................................................5
2. ABOUT THE HD717 ....................................................................................6
2.1 THE SERIAL COMMS CONTROLLER........................................................ 6
2.2 LOW RATE DATA INTERFACES ................................................................. 7
2.3 DIGITAL I/O INTERFACE.............................................................................. 9
3. CONTROLLING THE HD717.....................................................................10
3.1 SCC .................................................................................................................... 10
3.1.1 SCC I/O PORTS........................................................................................... 10
3.1.2 SCC BASIC CONFIGURATION ................................................................ 11
3.1.3 SCC TX/RX CLOCK SELECTION ............................................................ 14
3.1.4 SCC TRANSMIT PROCEDURE ................................................................ 17
3.1.5 SCC RECEIVE PROCEDURE.................................................................... 21
3.1.6 RS485 SUPPORT (Issue 2(+) HD717 & HD712,713 Cards Only) ............. 23
3.2 LOW RATE DATA .......................................................................................... 24
3.2.1 TRANSMIT.................................................................................................. 24
3.2.2 RECEIVE ..................................................................................................... 28
3.3 HANDLING INTERRUPTS............................................................................ 31
3.4 USING THE DIGITAL I/O PINS ................................................................... 35
4. HD717 REGISTER INTERFACE ...............................................................36
4.1 SCC CONTROL (0)
......................................................... 38
4.2 SCC DATA (1)
..................................................................... 38
4.3 IPR READ / IMR WRITE (2)
..................................... 39
4.4 LRD RX LO READ / TX LO WRITE (3)
.............. 40
4.5 LRD RX HI READ / TX HI WRITE (4)
................ 40
4.6 SUB REG DATA (5)
......................................................... 41
4.7 SUB REG IDX WRITE ONLY (6)
............................ 41
4.8 RX 4K FIFO READ / TX 4K FIFO WRITE (7)
. 43
