Delta Tau GEO BRICK LV User Manual

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Turbo PMAC User Manual 
40 
Talking to Turbo PMAC 
The values of I54 and the baud rates they produce are: 
I54 Baud 
Rate I54 Baud 
Rate I54 Baud 
Rate I54  Baud 
Rate 
0  600  4 2400 8 9600 12 38,400 
1 900 5 3600 9 
14,400 
13 57,600 
2  1200  6  4800  10 19,200 14  76,800 
3  1800  7  7200  11 28,800 15  115,200 
The baud rates produced by odd-number settings of I54 are only exact if the CPU frequency is an exact 
multiple of 30 MHz (technically, of 29.4912 MHz).  This is because the baud rates are created by dividing 
the CPU frequency by (256 * N), where N is an integer taken from a lookup table.  The frequency is not 
an exact match for odd settings of I54 and CPU frequencies that are not multiples of 30 MHz.  For lower 
baud rates of this type, the error is not significant.  However, serial communications at 115,200 baud is 
possible only if the CPU is running at an exact multiple of 30 MHz (actually an exact multiple of 29.4912 
MHz).  So to communicate at this rate, run an Option 5Cx 80 MHz CPU at 60 MHz, an Option 5Dx 100 
MHz CPU at 90 MHz, and an Option 5Ex 160 MHz CPU at 150 MHz by setting I52 to a lower value than 
the CPU is capable of. 
It is possible to download new operational firmware through the main serial port (see Resetting Turbo 
PMAC). 
Auxiliary Serial Port 
If Option 9T for the Turbo PMAC is ordered, directly or as part of an option package (as for the PMAC 
Ladder programming environment), a second serial port is provided on the Turbo PMAC.  This port is 
required for programming and monitoring the PMAC Ladder IEC-1131 PLC programs. 
Auxiliary Port Baud Rate 
The baud rate for the auxiliary serial port is set by variable I53.  At power-up reset, Turbo PMAC sets the 
active baud-rate-control register based on the setting of I53 and the CPU speed as set by I52, as the baud-
rate frequency is divided down from the CPU’s operational frequency.  The factory default baud rate is 
38,400.  If you wish to change the baud rate, you must change the setting of I53, copy this new setting to 
non-volatile memory with the SAVE command, then reset the Turbo PMAC.  Then you must re-establish 
communications at the new baud rate.  The values of I53 and the baud rates they produce are: 
I53 
Baud Rate  I53  Baud Rate  I53 
Baud Rate 
I53 
Baud Rate 
0 600 4 2400 8 9600 12 
38,400 
1 900 5 3600 9 14,400 
13 
57,600 
2  1200  6  4800  10 19,200 14 76,800 
3 1800 7 7200 11 28,800 15 
115,200 
The baud rates produced by odd-number settings of I53 are only exact if the CPU frequency is an exact 
multiple of 30 MHz (technically, of 29.4912 MHz).  This is because the baud rates are created by dividing 
the CPU frequency by (256 * N), where N is an integer taken from a lookup table.  The frequency is not 
an exact match for odd settings of I53 and CPU frequencies that are not multiples of 30 MHz.  For lower 
baud rates of this type, the error is not significant.  However, serial communications at 115,200 baud is 
only possible if the CPU is running at an exact multiple of 30 MHz (actually an exact multiple of 29.4912 
MHz).  So to communicate at this rate, run an Option 5Cx 80 MHz CPU at 60 MHz, an Option 5Dx 100 
MHz CPU at 90 MHz, and an Option 5Ex 160 MHz CPU at 150 MHz by setting I52 to a lower value than 
the CPU is capable of.