PIC16C74A-04/L Microchip Technology, PIC16C74A-04/L Datasheet - Page 3

• Manufacturer Part Number: PIC16C74A-04/L
• Description: IC MCU OTP 4KX14 A/D PWM 44PLCC
• Manufacturer: Microchip Technology
• Series: PIC® 16Cr

Specifications of PIC16C74A-04/L

• Core Size: 8-Bit
• Program Memory Size: 7KB (4K x 14)
• Oscillator Type: External
• Core Processor: PIC
• Speed: 4MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 33
• Program Memory Type: OTP
• Ram Size: 192 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 6 V
• Data Converters: A/D 8x8b
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 44-PLCC
• Controller Family/series: PIC16C
• No. Of I/o's: 33
• Ram Memory Size: 192Byte
• Cpu Speed: 10MHz
• No. Of Timers: 3
• No. Of Pwm: RoHS Compliant
• Processor Series: PIC16C
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 192 B
• Interface Type: I2C, SPI, USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 33
• Number Of Timers: 3
• Maximum Operating Temperature: + 70 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: ICE2000, DM163022
• Minimum Operating Temperature: 0 C
• On-chip Adc: 8 bit, 8 Channel
• Data Rom Size: 192 B
• A/d Bit Size: 8 bit
• A/d Channels Available: 8
• Height: 3.87 mm
• Length: 16.59 mm
• Supply Voltage (max): 6 V
• Supply Voltage (min): 4 V
• Width: 16.59 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC164309 - MODULE SKT FOR PM3 44PLCC444-1001 - DEMO BOARD FOR PICMICRO MCUDVA16XL441 - ADAPTER DEVICE ICE 44PLCC309-1040 - ADAPTER 44-PLCC ZIF TO 40-DIP309-1039 - ADAPTER 44-PLCC TO 40-DIPDV007003 - PROGRAMMER UNIVERSAL PROMATE II
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

1. Asynchronous Counter
EXAMPLE 1:
 2010 Microchip Technology Inc.
Update:
Critical Timing of code sequence for instructions following last write to TMR1L or TMR1H.
When Timer1 is started or updated, the timer
needs to see a falling edge from the external clock
source before a rising edge can increment the
counter. If writes to TMR1H and TMR1L are not
completed while the external clock pulse is still
high, Timer1 will miss counting the first clock pulse
after the update.
When using an external crystal, the pulse width
from rising to falling edge is temperature depen-
dent and may decrease with temperature. As a
result, the timer may require an additional oscilla-
tion to overflow.
Code examples are given for the affected devices:
• PIC12/14/16/17 devices – Example 1 and
• PIC18 devices – Example 3
Both examples include code to wait for Timer1 to
increment twice between the RTCisr and Update
labels.
BTFSC
GOTO
BTFSS
GOTO
BCF
BSF
BCF
BSF
BSF
Example 2
TMR1L,0
$-1
TMR1L,0
$-1
T1CON,TMR1CS
TMR1H,7
T1CON,TMR1ON
T1CON,TMR1C
T1CON,TMR1ON
PIC12/14/16/17 CODE EXAMPLE FOR 1 SECOND OVERFLOW PERIOD WITH 32.786
kHZ OSCILLATOR
;Timer has just incremented, 31 μs before next rising edge to
;complete reload
;Select system clock for Timer1
;Timer1 high byte 0x80
;Timer1 off
;Select external crystal
;Timer1 on
In PIC18 devices, it is not possible to reliably
update Timer1 in a low-priority interrupt. A high-
priority interrupt could occur at any time and
unexpectedly delay the TMR1 update.
PIC18 devices also include Timer3 which is
functionally identical to Timer1.
Work around
Switching Timer1 to the main system oscillator
after reloading, the timer ensures the timer will see
a falling edge before switching back to the external
clock source.
Due to the time from Timer1 overflow to the reload
being application specific, wait for the timer to
increment before beginning the reload sequence.
This ensures the timer does not miss a rising edge
during reload. The timing of the clock source
changing is critical and is detailed in Example 1
and Example 2.
TIMER1 MODULE
DS80329B-page 3