PIC14000-04 Microchip Technology, PIC14000-04 Datasheet - Page 76

• Manufacturer Part Number: PIC14000-04
• Description: 28-Pin Programmable Mixed Signal Controller
• Manufacturer: Microchip Technology

PIC14000
10.2
The PIC14000 can be operated with two different oscil-
lator options. The user can program a configuration
word (CONFIG<0>) to select one of these:
• HS
• IN
10.2.1
The PIC14000 includes an internal oscillator option
that offers additional cost and board-space savings. No
external components are required. The nominal
operating frequency is 4 MHz. The frequency is mea-
sured and stored into the calibration space in EPROM.
FIGURE 10-2: MISC REGISTER
DS40122B-page 76
B7
B6
B5
B4
B3
B2
B1
B0
9Eh
MISC
Read/Write
POR value 00h
Bit
Oscillator Configurations
INTERNAL OSCILLATOR CIRCUIT
High Speed Crystal/Ceramic Resonator
(CONFIG<0> =‘0’)
Internal oscillator (CONFIG<0> =‘1’)
(Default)
SMHOG
SPGNDB
SPGNDA
I
SMBus
INCLKEN
OSC2
OSC1
2
CSEL
Name
SMHOG
Bit 7
R/W
0
SMHOG enable
1 = Stretch I
Section 7.5.4). For pausing I
conversions.
0 = Disable I
Serial Port Ground Select
1 = PORTD<1:0> ground reference is the RD5/AN5 pin.
0 = PORTD<1:0> ground reference is V
Serial Port Ground Select
1 = PORTC<7:6> ground reference is the RA1/AN1 pin.
0 = PORTC<7:6> ground reference is V
I
1 = PORTD<1:0> are used as the I
0 = PORTC<7:6> are used as the I
SMBus-Compatibility Select
1 = SMBus compatibility mode is enabled. PORTC<7:6> and PORTD<1:0> have
SMBus-compatible input thresholds.
0 = SMBus-compatibility is disabled. PORTC<7:6> and PORTD<1:0> have Schmitt Trig-
ger input thresholds.
Oscillator Output Select (available in IN mode only).
1 = Output IN oscillator signal divided by four on OSC2 pin.
0 = Disconnect IN oscillator signal from OSC2 pin.
OSC2 output port bit (available in IN mode only).
Writes to this location affect the OSC2 pin in IN mode. Reads return the value of the
output latch.
OSC1 input port bit (available in IN mode only).
Reads from this location return the status of the OSC1 pin in IN mode. Writes have no
effect.
2
C Port select Bit.
SPGNDB SPGNDA
Bit 6
R/W
0
2
2
C CLK signal (hold low) when receive data buffer is full (refer to
C CLK stretch.
Bit 5
R/W
0
Preliminary
2
I
C transfers while preventing interruptions of A/D
2
Bit 4
CSEL
R/W
0
By selecting IN mode OSC1/PBTN becomes a digital
input (with weak internal pull-up resistor) and can be
read via bit MISC<0>. Writes to this location have no
effect. The OSC1/PBTN input is capable of generating
an interrupt to the CPU if enabled (Section 10.6). Also,
the OSC2 pin becomes a digital output for general pur-
pose use and is accessed via MISC<1>. Writes to this bit
directly affect the OSC2 pin. Reading this bit returns the
contents of the output latch. The MISC register format is
shown in Figure 10-2.
The OSC2 pin can also output the IN oscillator fre-
quency,
(MISC<2>).
2
2
Note:
C clock and data lines.
C clock and data lines.
Function
SS
SS
SMBUS
Bit 3
R/W
.
.
0
divided-by-four,
The OSC2 output buffer provides less drive
than standard I/O.
INCLKEN
Bit 2
R/W
0
1996 Microchip Technology Inc.
by
OSC2
Bit 1
R/W
setting
0
INCLKEN
OSC1
Bit 0
R
X