i

Chapter 1. General Description

1.1

Introduction .................................................................................................................................... 1-1

1.2

SCC’s Capabilities ......................................................................................................................... 1-2

1.3

Block Diagram ............................................................................................................................... 1-4

1.4

Pin Descriptions ............................................................................................................................. 1-5

1.4.1

Pins Common to both Z85X30 and Z80X30 .................................................................... 1-7

1.4.2

Pin Descriptions, (Z85X30 Only) ...................................................................................... 1-8

1.4.3

Pin Descriptions, (Z80X30 Only) ...................................................................................... 1-9

Chapter 2. Interfacing the SCC/ESCC

2.1

Introduction .................................................................................................................................... 2-1

2.2

Z80X30 Interface Timing ................................................................................................................ 2-1

2.2.1

Z80X30 Read Cycle Timing ............................................................................................. 2-2

2.2.2

Z80X30 Write Cycle Timing .............................................................................................. 2-3

2.2.3

Z80X30 Interrupt Acknowledge Cycle Timing .................................................................. 2-4

2.2.4

Z80X30 Register Access .................................................................................................. 2-5

2.2.5

Z80C30 Register Enhancement ....................................................................................... 2-8

2.2.6

Z80230 Register Enhancements ...................................................................................... 2-8

2.2.7

Z80X30 Reset .................................................................................................................. 2-9

2.3

Z85X30 Interface Timing ............................................................................................................. 2-10

2.3.1

Z85X30 Read Cycle Timing ........................................................................................... 2-10

2.3.2

Z85X30 Write Cycle Timing ............................................................................................ 2-11

2.3.3

Z85X30 Interrupt Acknowledge Cycle Timing ................................................................ 2-11

2.3.4

Z85X30 Register Access ................................................................................................ 2-12

2.3.5

Z85C30 Register Enhancement ..................................................................................... 2-14

2.3.6

Z85C30/Z85230 Register Enhancements ...................................................................... 2-14

2.3.7

Z85X30 Reset ................................................................................................................ 2-15

2.4

Interface Programming ................................................................................................................ 2-15

2.4.1

I/O Programming Introduction ........................................................................................ 2-15

2.4.2

Polling ............................................................................................................................ 2-16

2.4.3

Interrupts ........................................................................................................................ 2-16

2.4.4

Interrupt Control ............................................................................................................. 2-17

2.4.5

Daisy-Chain Resolution .................................................................................................. 2-19

2.4.6

Interrupt Acknowledge ................................................................................................... 2-21

2.4.7

The Receiver Interrupt ................................................................................................... 2-21

2.4.8

Transmit Interrupts and Transmit Buffer Empty Bit ........................................................ 2-25

2.4.9

External/Status Interrupts ............................................................................................... 2-31

2.5

Block/DMA Transfer ..................................................................................................................... 2-33

2.5.1

Block Transfers .............................................................................................................. 2-33

2.5.2

DMA Requests ............................................................................................................... 2-36

2.6

Test Functions ............................................................................................................................. 2-41

2.6.1

Local Loopback .............................................................................................................. 2-41

2.6.2

Auto Echo ....................................................................................................................... 2-41

UM010901-0601