Megatel Quark/100 Specifications download pdf (Page 69)

3.

where

fE

is

the frequency of the E-clock

and

N

is

the value in the

Timer

2 latch.

Connectlng

jumpers

J3

and

J4

will connect the

PB7

I/O

line

from

the

VIA

to

the

CB1

control

line of the

VIA.

This

allows

Timer

1,

normally

used

to generate the transmit

and

receive

clocks for the full-duplex

serial

port, to generate the

simplex

serial

port clock

as

well. I

However,

split

baud

rates

on

the full-duplex channel are

not

possible

when

Timer

1

is

used

in

this

way.

---

--

TABLE

V

SYNCHRONOUS

ADDRESS

MULTIPLEXER

ADDRESS

ASSIGNMENTS

ADDRESS

CONTROL

REGISTER

SET/CLEAR

REMARKS

(HEX)

BIT

---------

------

-

FFBO

va

CLR

Norma

lly c lea

red

FF81

va

SET

FF82

V1

CLR

Normally

cleared

FF83

V1

SET

FF84

V2

CLR

Cleared for

Alphanumeric

Mode

FF85

V2

SET

Set for Graphics

Mode

FF86

Fa

CLR

Start

address

bit

10

FF87

FO

SET

FF88

F1

CLR

Start address

bit

11

FF89

F1

SET

FFSA

F2

CLR

Start

address

bit

12

FF8B

F2

SET

FF8C

F3

CLR

Start address

bit

13

FF8D

F3

SET

FF8E

F4

CLR

Norma

lly set

FF8F

F4

SET

FF90

F5

CLR

Start address

bit

14

FF91

F5

SET

FF92

F6

CLR

Start

address

bit

15

FF93

F6

SET

FF94

P1

CLR

Page

bit

FF95

P1

SET

FF96

Ra

CLR

Norma

lly cleared

FF97

RO

SET

FF98

R1

CLR

Norma

lly c lea

red

FF99

R1

SET

FF9A

Ma

CLR

Norma

lly cleared

FF9B

MO

SET

FF9C

M1

CLR

Norma

lly set

FF9D

M1

SET

FF9E

TV

CLR

Map

type-see sec

T/1.1

FF9F

TV

SET

(Norma

lly

set)

Notes:

1.

To

set or clear

any

of

the

bits

in

SAM

registers,

load

the address in the

above

table

corresponding to the

bit

to

be

set

or

cleared into the

HL

register,

and

then execute a

CALL

to

the subroutine at location

OBhex.

(Note

that

this

routine

alters

the contents of

the

C

register.)

-_._---------_.---_._._--------------

Megatel

Computer

Technologies Toronto,

Canada

Appendix

Page

A-8

1 2 ... 64 65 66 67 68 69 70 71 72 73 74 ... 85 86

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