cop87l88gw National Semiconductor Corporation, cop87l88gw Datasheet - Page 9

• Manufacturer Part Number: cop87l88gw
• Description: One-time Programmable Otp Microcontroller
• Manufacturer: National Semiconductor Corporation

Oscillator Circuits
Table I shows the component values required for various
standard crystal values
Current Drain
The total current drain of the chip depends on
1 Oscillator operation mode I1
2 Internal switching current I2
3 Internal leakage current I3
4 Output source current I4
5 DC current caused by external input not at V
Thus the total current drain It is given as
To reduce the total current drain each of the above compo-
nents must be minimum
The chip will draw more current as the CKI input frequency
increases up to the maximum 10 MHz value Operating with
a crystal network will draw more current than an external
Square-wave Switching current governed by the equation
below can be reduced by lowering voltage and frequency
Leakage current can be reduced by lowering voltage and
temperature The other two items can be reduced by care-
fully designing the end-user’s system
where C
Control Registers
CNTRL Register (Address X’00EE)
The Timer1 (T1) and MICROWIRE PLUS control register
contains the following bits
SL1
SL0
IEDG External interrupt edge polarity select (0
MSEL Selects G5 and G4 as MICROWIRE PLUS signals
T1C0 Timer T1 Start Stop control in timer modes 1 and 2
T1C1 Timer T1 mode control bit
T1C2 Timer T1 mode control bit
T1C3 Timer T1 mode control bit
(k )
T1C3
TABLE I CrystaI Oscillator Configuration T
Bit 7
R1
0
0
0
GND I5
V
Select the MICROWIRE PLUS clock divide by (00
2 01
edge 1
SK and SO respectively
T1 Underflow Interrupt Pending Flag in timer mode 3
f
(M )
T1C2
R2
e
e
e
1
1
1
equivalent capacitance of the chip
operating voltage
CKI frequency
e
e
It
(pF)
4 1x
200
T1C1
C1
30
30
e
Falling edge)
I1
I2
e
100–150
a
30–36
30–36
T1C0
e
8)
(pF)
I2
C2
C
a
c
(Continued)
I3
V
MSEL
a
c
CKI Freq
(MHz)
0 455
I4
f
10
4
a
IEDG
I5
Conditions
V
V
V
A
SL1
CC
CC
CC
e
e
e
e
e
25 C
CC
Rising
Bit 0
SL0
5V
5V
5V
or
e
9
PSW Register (Address X’00EF)
The PSW register contains the following select bits
GIE
EXEN
BUSY
EXPND
T1ENA
T1PNDA Timer T1 Interrupt Pending Flag (Autoreload RA
C
HC
The Half-Carry fIag is aIso affected by aII the instructions
that affect the Carry fIag The SC (Set Carry) and RC (Reset
Carry) instructions wilI respectiveIy set or clear both the car-
ry flags In addition to the SC and RC instructions ADC
SUBC RRC and RLC instructions affect the Carry and Half
Carry fIags
ICNTRL Register (Address X’00E8)
The ICNTRL register contains the foIlowing bits
T1ENB
T1PNDB Timer T1 Interrupt Pending Flag for T1B capture
T0EN
T0PND
LPEN
Bit 7 couId be used as a flag
T2CNTRL Register (Address X’00C6)
The T2CNTRL register contains the following bits
T2ENB
T2PNDB Timer T2 Interrupt Pending Flag for T2B capture
T2ENA
T2PNDA Timer T2 Interrupt Pending Flag (Auto reload RA
T2C0
T2C1
T2C2
T2C3
Unused LPEN T0PND T0EN
Bit 7
Bit 7
T2C3 T2C2 T2C1 T2C0 T2PNDA T2ENA T2PNDB T2ENB
Bit 7
WEN
WPND MICROWIRE PLUS interrupt pending
HC
C
GIobaI interrupt enable (enables interrupts)
EnabIe externaI interrupt
MICROWIRE PLUS busy shifting flag
ExternaI interrupt pending
Timer T1 Interrupt Enable for Timer Underflow or
T1A Input capture edge
in mode 1 T1 Underflow in Mode 2 T1A capture
edge in mode 3)
Carry FIag
Half Carry Flag
Timer T1 Interrupt Enable for T1B Input capture
edge
edge
EnabIe MICROWIRE PLUS interrupt
Timer T0 Interrupt Enable (Bit 12 toggle)
Timer T0 Interrupt pending
L Port Interrupt Enable (Multi-Input Wake up In-
terrupt)
Timer T2 Interrupt Enable for T2B Input capture
edge
edge
Timer T2 Interrupt Enable for Timer Underflow or
T2A Input capture edge
in mode 1 T2 Underflow in mode 2 T2A capture
edge in mode 3)
Timer T2 Start Stop control in timer modes 1 and
2 Timer T2 Underflow Interrupt Pending Flag in
timer mode 3
Timer T2 mode control bit
Timer T2 mode control bit
Timer T2 mode control bit
T1PNDA
T1ENA
WPND
EXPND
WEN T1PNDB T1ENB
BUSY
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EXEN
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Bit 0
GIE
Bit 0
Bit 0