SAN3010

sames

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sames

sames

10/13

PAGE

4

LOC

OBJ

LINE

SOURCE

4057 D9FE

161

Del7a:

djnz

R1,$

; =256*2 machine cycles

4059 DAFC

162

djnz

R2,Del7a

; =2 machine cycles

163

; 28*(256*2+2)=14392mc's=15.6ms

164

405B 22

165

ret

; return from subroutine

166

167

168

;**************************************************************

169

; Subroutine GetScTb

170

;**************************************************************

171

; this subroutine loads the Reg5..Reg7 registers according to

172

; the keycode passed by the accumulator contents.

173

; valid keycodes are

0.....31 (dec) = 0....1F (Hex)

174

175

405C 904074

176

GetScTb:mov

dptr,#Scantbl

; calculate offset Address:

405F 75F003

177

mov

B,#3

; scantable startaddress

4062 A4

178

mul

AB

;

+ (keycode *3)

4063 F5F0

179

mov

B,A

; save offset address

180

4065 93

181

movc

A,@A+DPTR

; get scan table: Row X

4066 FD

182

mov

R5,A

; RowX

183

4067 E5F0

184

mov

A,B

4069 04

185

inc

A

; get next code

406A F5F0

186

mov

B,A

; save

406C 93

187

movc

A,@A+DPTR

; get scan table: Row X

406D FE

188

mov

R6,A

; RowY

189

406E E5F0

190

mov

A,B

4070 04

191

inc

A

; get next code

4071 93

192

movc

A,@A+DPTR

; get scan table: Row X

4072 FF

193

mov

R7,A

; ColX

194

4073 22

195

ret

196

197

; Scan table: the three constants indicate the rows/columns

198

;

to be driven in the SCAN1....SCAN3 phase

199

;

4074 00

200

Scantbl:db

Row1,Row1,Col1

;

key "Pgm/Mt, keycode= 0

4075 00

4076 04

4077 00

201

db

Row1,Row1,Col2

;

key "1"

, keycode= 1

4078 00

4079 05

407A 00

202

db

Row1,Row1,Col3

;

key "2"

, keycode= 2

407B 00

407C 06

407D 00

203

db

Row1,Row1,Col4

;

key "3"

, keycode= 3

407E 00

407F 07

4080 01

204

db

Row2,Row2,Col1

;

key "4"

, keycode= 4

4081 01

4082 04

4083 01

205

db

Row2,Row2,Col2

;

key "5"

, keycode= 5