47
78
UP3_1
/ UTXD
TTL I/O, Slew rate
50K pull_up, 4mA
Programmable bi-directional I/O.
Alternate function : TXD. Serial transmit data.
77
UP3_0
/ URXD
TTL I/O, Slew rate
50K pull_up, 4mA
Programmable bi-directional I/O.
Alternate function : RXD. Serial receive data.
75
UXI/O4
TTL otuput, Slew
rate, 8mA
Microprocessor clock for ICE mode or general output O4 for non-ice
mode
73~ 66
UA[7:0]
/ O[15:8]
TTL I/O, Slew rate
programmable
Lower address bus output for external device.
Alternate function : Programmable output.
57
UP3_7
/ URD_
TTL I/O, Slew rate
SMT, 50K pull_up,
4mA
Programmable bi-directional I/O.
Alternate function : RD_. Data write signal.
56
UP3_6
/ UWR_
TTL I/O, Slew rate
SMT, 50K pull_up,
4mA
Programmable bi-directional I/O.
Alternate function : WR_. Data write signal.
54
UP3_3
/ UINT1_
TTL I/O, Slew rate
50K pull_up, 4mA
Programmable bi-directional I/O.
Alternate function : INT1_. External interrupt 0.
53
UP3_2
/ UINT0_
TTL I/O, Slew rate
50K pull_up, 4mA
Programmable bi-directional I/O.
Alternate function : INT0_. External interrupt 0.
43 ~ 50
UP0_[7:0]
/ UAD[7:0]
TTL I/O, Slew rate,
programmable
Programmable bi-directional I/O.
Alternate function : AD[7:0]. Lower address/data bus output for
external device.
38
UALE
TTL I/O, 50K
pull_up, 4mA
Address latch enable output, active high.
Alternate function : Programmable GPIO.
37
UPSEN_
TTL I/O, 50K
pull_up, 4mA
Programmable store enable output, active low. PSEN_ enables the
external ROM output port.
Alternate function : Programmable output.
36
UP1_0
/ UA16
TTL I/O, Slew rate
50K pull_up, 4mA
Programmable bi-directional I/O.
Alternate function : A16. Address bit 16 output.
35, 34, 28, 29
30, 31, 32, 33
UP2_[7:0]
/ UA[15:8]
TTL I/O, Slew rate
programmable
Programmable bi-directional I/O.
Alternate function : A[15:8]. Upper address bus input/output.
39
DVDD5
Power(5V)
Power pin for output pad circuitry.
42
DGND
Ground
Ground pin for output pad circuitry.
51
DGND
Ground
Ground pin for internal digital circuitry.
55
DVDD3
Power(3.3V)
Power pin for internal digital circuitry.
74
DVDD5
Power(5V)
Power pin for output pad circuitry.
76
DGND
Ground
Ground pin for output pad circuitry.
98
DGND
Ground
Ground pin for internal digital circuitry.
102
DVDD3
Power(3.3V)
Power pin for internal digital circuitry.
Xtal Interface
40
XTALI
Input
Xtal input. The working frequency is 33.8688 MHz.
41
XTALO
Output
Xtal output.
Varipitch VCO Interface
58
VPVDD
Analog power(5V)
Power pin for varipitch VCO circuitry.
59
VCOCIN
Analog Input
Connect capacitor for compensator loop filter.