Z80230 View Datasheet(PDF) - Zilog

Part Name

Description

Manufacturer

Z80230

Zilog SCC Serial Communication Controller

Zilog 

SCC™/ESCC™ User’s Manual

Data Communication Modes

Modem Controls. Up to two modem control signals asso- Initialization. The initialization sequence for the receiver

ciated with the receiver are available in Synchronous in character-oriented mode is WR4 first, to select the

4 modes: /DTR//REQ and /DCD. The /DTR//REQ pin carries mode, then WR10 to modify it if necessary; WR6 and WR7

the inverted state of the DTR bit (D7) in WR5 unless this to program the sync characters; WR3 and WR5 to select

pin has been programmed to carry a DMA Request on the various options. At this point the other registers are ini-

Transmit signal. The /DCD pin is ordinarily a simple input tialized as necessary. When all this is completed, the re-

to the DCD bit in RR0. However, if the Auto Enables mode ceiver is enabled by setting bit D0 of WR3 to a one. A sum-

is selected by setting D5 of WR3 to 1, this pin becomes an mary is shown in Table 4-8. A detailed example of using

enable for the receiver. Therefore, if Auto Enables is ON the SCC in 16-bit sync mode is available in the application

and the /DCD pin is High, the receiver is disabled; while note “SCC in Binary Synchronous Communications.”

the /DCD pin is Low, the receiver is enabled.

Note that with Auto Enables mode enabled, when /DCD

goes inactive, the receiver stops immediately and the

character being assembled is lost.

UM010901-0601

4-15

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