"PULL41998 TENEMOS ESPERANZA ESTO LO DICE EN LA AYUDA DEL PBP" debemos enfocarnos en la parte que resalte de futcia,
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HSERIN {
ParityLabel,}{
Timeout,
Label,}[
Item{,...}]
Receive one or more items from the hardware serial port on devices that support asynchronous serial communications in hardware.
HSERIN is one of several built-in asynchronous serial functions. It can only be used with devices that have a hardware USART. See the device data sheet for information on the serial input pin and other parameters. The serial parameters and baud rate are specified using
DEFINEs:
' Set receive register to receiver enabled
DEFINE HSER_RCSTA 90h
' Set transmit register to transmitter enabled
DEFINE HSER_TXSTA 20h
' Set baud rate
DEFINE HSER_BAUD 2400
' Set SPBRG directly (normally set by HSER_BAUD)
DEFINE HSER_SPBRG 25
HSERIN assumes a 4MHz oscillator when calculating the baud rate. To maintain the proper baud rate timing with other oscillator values, be sure to
DEFINE the OSC setting to the new oscillator value. An optional Timeout and
Label may be included to allow the program to continue if a character is not received within a certain amount of time. Timeout is specified in 1 millisecond units.
The serial data format defaults to 8N1, 8 data bits, no parity bit and 1 stop bit. 7E1 (7 data bits, even parity, 1 stop bit) or 7O1 (7data bits, odd parity, 1 stop bit) can be enabled using one of the following
DEFINEs:
' Use only if even parity desired
DEFINE HSER_EVEN 1
' Use only if odd parity desired
DEFINE HSER_ODD 1
The parity setting, along with all of the other HSER
DEFINEs, affect both HERIN and HSEROUT. An optional ParityLabel may be included in the statement. The program will continue at this location if a character with a parity error is received. It should only be used if parity is enabled using one of the preceding
DEFINEs. Since the serial reception is done in hardware, it is not possible to set the levels to an inverted state to eliminate an RS-232 driver. Therefore a suitable driver should be used with
HSERIN.
HSERIN supports the same data modifiers that
SERIN2 does.
Modifier
Operation
BIN{1..16}
Receive binary digits
DEC{1..5}
Receive decimal digits
HEX{1..4}
Receive hexadecimal digits
SKIP n
Skip n received characters
STR ArrayVar\n{\c}
Receive string of n characters optionally ended in character c
WAIT ( )
Wait for sequence of characters
WAITSTR ArrayVar{\n}
Wait for character string
On 17Cxxx devices with 2 serial ports,
HSERIN will only access the first port. The second port should be set up and read by accessing the registers directly.
See Also
SERIN
SERIN2
SEROUT
SEROUT2
HSEROUT
Copyright © 1999 microEngineering Labs, Inc.
All rights reserved.
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