Z86D990 Datasheet, PDF (78/102 Pages) Zilog, Inc. – Low-Voltage Micro controllers with ADC

Z86D990/Z86D991 OTP and Z86L99X ROM
Low-Voltage Microcontrollers with ADC
71
Port 6 Control and Mode Registers (P6 and P6M)
Port 6 is a general-purpose 8-bit, bidirectional I/O port, as shown in Table 32.
Each of the eight Port 6 I/O lines can be independently programmed as either
input or output using the Port 6 Mode Register (see Table 33.)
Table 32. P6 Register [Group/Bank 00h, Register 6 (R6)]
Bit
7
6
5
4
Bit/Field Port 6 Data
R/W
R/W R/W R/W R/W
Reset
X
X
X
X
R = Read, W = Write, X = Indeterminate
Bit
Position
Bit/Field
R/W Value
76543210 Port 6 Data
R/W Data
3
2
1
0
R/W R/W R/W R/W
X
X
X
X
Description
Port 6 Input/Output Register
Table 33. P6M Register (Group/Bank 0Fh, Register 6)
Bit
7
6
5
4
Bit/Field P67M P66M P65M P64M
R/W
R/W R/W R/W R/W
Reset
1
1
1
1
R = Read, W = Write, X = Indeterminate
Bit
Position
Bit/Field
R/W Value
76543210 Port 6 Mode
(by bit)
Select
R/W 1
0
3
P63M
R/W
1
2
P62M
R/W
1
Description
Input
Output
1
P61M
R/W
1
0
P60M
R/W
1
A bit set to 1 in the P6M Register configures the corresponding bit in Port 6 as an
input, while a bit set to 0 configures an output line.
Timer Control Registers—General-Purpose Timer (T1)
The Z86D99/Z86L99 family provides one standard 8-bit Z8 counter/timer, T1,
driven by its own 6-bit prescaler, PRE1. T1 is independent of the processor
instruction sequence, relieving software from time-critical operations such as
interval timing or event counting. There are three registers that control the opera-
tion of T1: T1 Data Register (T1), T1 Mode Register (TMR), and T1 Prescale Reg-
ister (PRE1). Because the timer, prescaler, and mode register are mapped into
the standard Z8 register file, the software can treat the counter/timer as a general-
purpose register, thus eliminating the requirement for special instructions.
PS003807-1002
PRELIMINARY