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Details, datasheet, quote on part number:NT6868AH-10088
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Datasheet text preview:
NT6868A
Keyboard Controller
Features
n n n n n Built-in 6502 8-bit CPU 2 MHz CPU operation frequency 4K bytes of ROM 128 bytes of SRAM One 8-bit programmable base timer with 1 - 256 µsec interval n 29 programmable bi-directional I/O pins n 3 LED direct sink pins with internal serial resistors n Mask optional for built-in RC oscillator with an external resistor or external ceramic resonator applied n Watch-dog timer n Built-in power-on reset n Built-in low voltage reset n CMOS technology for low power consumption n Available in 40 pin DIP package and 40 pad CHIP FORM
General Description
NT6868A is a single chip micro-controller for keyboard applications. It incorporates a 6502 8-bit CPU core, 4K bytes of ROM, and 128 bytes of RAM used as working RAM and stack area. It also includes 29 programmable bi-directional I/O pins and one 8-bit pre-loadable base timer. Additionally, it includes a built-in low voltage reset, a 4MHz RC oscillator that requires only a resistor externally applied or a 4MHz ceramic resonator, and a watch-dog timer that prevents system standstill.
Pin Configuration
GND NC DATA CLK P30 P31 P32 P33 P34 RESET P00 P01 P02 P03 P04 P05 P06 P07 P10 P11 1 2 3 4 5 6 7 8 40 39 38 37 36 35 34 33 OSCI R/OSCO VDD LED2 LED1 LED0 P27 P26 P25 P24 P23 P22 P21 P20 P17 P16 P15 P14 P13 P12
Pad Configuration
P 1 7 P 1 6 P 1 5 P 1 4 P 1 3 P 1 2 P 1 1 P 1 0 P 0 7 P 0 6
26
25
24
23
22
21
20
19
18
17
16 15
P05 P04 P03 P02 P01 P00 RESET P34 P33 P32
P20 P21 P22 P23 P24 P25 P26 P27 LED0 LED1
27 28 29 30 31 32 33 34 35 36 37 38 39 40 1 2 3 4 5
14 13 12 11 10 9 8 7
NT6868A
9 10 11 12 13 14 15 16 17 18 19 20
32 31 30 29 28 27 26 25 24 23 22 21
NT6868AH
6
P31
L E D 2
V
D D
R / O S C O
O S C I
G N D
N C
D A T A
C L K
P 3 0
1
V2.1
NT6868A
Block Diagram
CLK TIMING GENERATOR (RC OSC/CERAMIC RESONATOR: 4MHz) 4K BYTES ROM
DATA
LED0
LED1
6502 CPU
128 BYTES SRAM + STACK
LED2
I/O PORTS
P00 - P07
INT. CONTROLLER
WATCH DOG TIMER
P10 - P17
P20 - P27 RESET VDD GND POWER-ON RESET/ LOW VOLTAGE RESET BASE TIMER P30 - P34
Pin and Pad Descriptions
Pin No. 1 2 3 4 5 - 9, 11 - 34 10 35 - 37 38 39 40 Pad No. 1 2 3 4 5 - 9, 11 - 34 10 35 - 37 38 39 40 Designation GND NC DATA CLK P30 - P34, P00 - P27
RESET
I/O P I/O I/O I/O I O P I Ground pin
Description No connection, recommended to connect VDD or floating I/O, 10K pull-up resistor for communication I/O, 10K pull-up resistor for communication Bi-directional I/O pins
RESET signal input pin with internal pull up resistor; Active low
LED0 LED2 VDD R/OSCO OSCI
LED direct sink pins Power supply 47K resistor connected for RC OSC or 4MHz ceramic resonator connected No connection for RC OSC, connected for 4MHz ceramic resonator
* Under the constraint of the maximum frequency variation, (F/F)max, ±1%, code 3 (ceramic resonator option) must be selected and pin 39 and pin 40 are connected to a ceramic resonator. If (F/F)max, ±10%, code 1 (RC OSC option) is recommended to be selected and pin39 connects a 47K resistor with, ±1% accuracy to VDD and pin 40 is floating.
2
NT6868A
Functional Description 6502 CPU
6502 is an 8-bit CPU. Refer to 6502 data sheet for details.
7 ACCUMULATOR A 7 INDEX REGISTER X
0 0000 SRAM 0 007F UNUSED 00C0 0 INDEX REGISTER Y SYSTEM REGISTERS 00CF STACK PTR
7
15 PROGRAM COUNTER PC 7 S 7 S V B D I Z
0
UNUSED
0 STACK POINTER SP 0 C STATUS REGISTER P
F000
USER ROM
FFFA CARRY FFFB ZERO INTERRUPT MASK DECIMAL MODE BREAK OVERFOLW SIGN FFFC RST-L FFFD RST-H FFFE IRQ-L FFFF IRQ-H IRQ VECTOR NMI-H NMI-L NMI VECTOR
Figure 1. 6502 CPU Registers and Status Flags
Figure 2. NT6868A Memory Map
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