Maxim Integrated High-Speed Microcontroller Users Guide: Network Microcontroller Supplement - Manual (Page 191)

High-Speed Microcontroller User’s
Guide: Network Microcontroller
Supplement
191
UTILITY FUNCTIONS
crc16
Description: int crc16(
int crc,
/* initial CRC value */
unsigned char value); /* value to include in the CRC calculation */
The crc16 function computes the CRC-16 of a byte given an initial CRC value.
mem_clear
Description: void mem_clear(
void *target,
/* pointer to start of target memory to clear */
int length); /* length (in number of bytes) to clear */
The mem_clear function clears a block of memory of length beginning at starting address specified by *target.
mem_copy
Description: void mem_copy(
void *source,
/* pointer to the start of the source buffer */
void *target, /* pointer to the start of the target buffer*/
int length); /* length of data to be copied */
The mem_copy function copies a block of memory. If the source and target memory buffers overlap, there is no guarantee
that the source bytes are not overwritten prior to being copied to the target.
INPUT DESCRIPTION OUTPUT DESCRIPTION
B:ACC
DPTR0
DPTR1
length
*source
*target
DPTR0
DPTR1
*source+length
*target+length
Example: MOV B, #high(MEMLENGTH)
MOV A, #low(MEMLENGTH)
MOV DPTR, #SOURCE
INC DPS
MOV DPTR, #TARGET
INC DPS
ROMCALL mem_copy
INPUT DESCRIPTION OUTPUT DESCRIPTION
B:ACC
DPTR0
length
*target
-
Example: MOV B, #high(MEMLENGTH)
MOV A, #low(MEMLENGTH)
MOV DPTR, #MEMTOCLEAR
ROMCALL mem_clear
INPUT DESCRIPTION OUTPUT DESCRIPTION
ACC
R1:R0
value
crc
R1:R0 CRC-16 return value
Example: MOV R1, #0
MOV R0, #0
MOV DPTR, #bytelocation
MOVX A, @DPTR
ROMCALL crc16
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