Intel 8253 - Page 649

15
FIGURE 19. KEYBOARD AND DISPLAY INTERFACE
FIGURE 20. KEYBOARD AND TERMINAL ADDRESS
INTERFACE
FIGURE 21. DIGITAL TO ANALOG, ANALOG TO DIGITAL FIGURE 22. BASIC CRT CONTROLLER INTERFACE
PA0
PA1
PA2
PA3
PA4
PA5
PA6
PA7
PC4
PC5
PB0
PB1
PB2
PB3
PB4
PB5
PB6
PB7
PC1
PC2
STROBE
ACK
DATA READY
ACK
MODE 1
(OUTPUT)
82C55A
MODE 1
(INPUT)
FULLY
DECODED
INTERRUPT
REQUEST
INTERRUPT
REQUEST
PC3
PC6
PC7
KEYBOARD
R0
R1
R2
R3
R4
R5
SHIFT
CONTROL
B0
B1
B2
B3
B4
B5
BACKSPACE
CLEAR
BURROUGHS
SELF-SCAN
DISPLAY
BLANKING
CANCEL WORD
STROBE
ACK
FULLY
DECODED
KEYBOARD
R0
R1
R2
R3
R4
R5
SHIFT
CONTROL
PA0
PA1
PA2
PA3
PA4
PA5
PA6
PA7
PC4
PC5
PC6
PC7
PB0
PB1
PB2
PB3
PB4
PB5
PB6
PB7
MODE 0
(INPUT)
82C55A
MODE 1
(INPUT)
PC3
BUST LT
TEST LT
TERMINAL
ADDRESS
INTERRUPT
REQUEST
PA0
PA1
PA2
PA3
PA4
PA5
PA6
PA7
PC4
PC5
PC6
PC7
PC1
PC2
PC3
PB0
PB1
PB2
PC4
PC5
LSB
STB DATA
MAB
MODE 0
(INPUT)
82C55A
MODE 0
(OUTPUT)
12-BIT
A/D
CONVERTER
(DAC)
PC0
PB3
PC6
PC7
BIT
SET/RESET
SAMPLE EN
STB
LSB
8-BIT
D/A
CONVERTER
(ADC)
ANALOG
INPUT
ANALOG
OUTPUT
PA0
PA1
PA2
PA3
PA4
PA5
PA6
PA7
PC7
PC6
PC5
PC4
PB0
PB1
PB2
PB3
PB4
PB5
PB6
PB7
PC2
PC1
MODE 0
(OUTPUT)
82C55A
MODE 1
(OUTPUT)
PC3
DATA READY
ACK
CRT CONTROLLER
• CHARACTER GEN.
INTERRUPT
REQUEST
• REFRESH BUFFER
R0
R1
R2
R3
R4
R5
SHIFT
CONTROL
ROW STB
COLUMN STB
CURSOR H/V STB
CURSOR/ROW/COLUMN
• CURSOR CONTROL
PC0
ADDRESS
H&V
BLANKED
BLACK/WHITE
82C55A