Mitsubishi Electric Q12DCCPU-V - Page 434

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13.3 Data Communications Using CPU Shared Memory
13.3.4 Data communications without using auto refresh
13
COMMUNICATIONS BETWEEN CPU MODULES
<Interlock program example>
Depending on the following timing, old and new data for each CPU may be mixed
(data separation).
• Writing data to the user setting area in another CPU and reading another
CPU's user setting area data from the host CPU
• Writing data to the user setting area in the host CPU and reading host CPU's
user setting area data from another CPU
The following explains how to avoid data separation in data communications
through user setting areas.
Figure 13.25 shows an example, in which an interlock is programmed for sending
data from CPU No.1 (C Controller module) to CPU No.2 (C Controller module)
using user setting areas in the multiple CPU high speed transmission areas.
Sending side program for CPU No.1 (C Controller module)
{
:
unsigned short usBuf; /* Data storage destination */
unsigned short pusData[128]; /* Data storage destination */
:
/****************************************************************/
/* CPU No.1 send data are written to the user setting area. */
/****************************************************************/
sRet = QBF_ToBuf(lPath, 0x3E0, 10000, 10, pusData, 128);
if( sRet != 0) return(sRet);
/****************************************************************/
/* CPU No.1 data set completion bit turns ON. */
/****************************************************************/
usBuf = 1;
sRet = QBF_ToBuf(lPath, 0x3E0, 10010, 1, &usBuf, 1);
if( sRet != 0) return(sRet);
/****************************************************************/
/* The ON status of CPU No.2 data processing completion bit is detected.*/
/****************************************************************/
while(1){
sRet = QBF_FromBuf(lPath, 0x3E1, 10000, 1, &usBuf, 1);
if( sRet != 0) return(sRet);
if( (usBuf & 0x1) == 0x0 ) break; /* When 0 is set, processing gets out from the loop. */
taskDelay(2);
}
/****************************************************************/
/* CPU No.1 data set completion bit turns OFF. */
/****************************************************************/
usBuf = 0;
sRet = QBF_ToBuf(lPath, 0x3E0, 10010, 1, &usBuf, 1);
if( sRet != 0) return(sRet);
}
Figure 13.25 Interlock program example
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