Model 6485 Picoammeter Instruction Manual Status Structure 10-5
Programming and reading registers
Programming enable registers
The only registers that can be programmed by the user are the enable registers. All other
registers in the status structure are read-only registers. The following explains how to
ascertain the parameter values for the various commands used to program enable registers.
The actual commands are covered later in this section (Table 10-3 and Table 10-6).
A command to program an event enable register is sent with a parameter value that deter-
mines the desired state (0 or 1) of each bit in the appropriate register. An enable register
can be programmed using any of the following data formats for the parameter value;
binary, decimal, hexadecimal, or octal.
The bit positions of the register (Figure 10-1) indicate the binary parameter value. For
example, if you wish to sets bits B4, B3, and B1, the binary value would be 11010 (where
B4=1, B3=1, B1=1 and all other bits are 0). When you use one of the other formats, con-
vert the binary number to its decimal, hexadecimal, or octal equivalent:
Binary 11010 = Decimal 26 = Hexadecimal 1A = Octal 32
Note that Figure 10-2 includes the decimal weight for each register bit. To set bits B4, B3,
and B1, the decimal parameter value would be the sum of the decimal weights for those
bits (16+8+2 = 26).
The <NDN> (non-decimal numeric) parameter type is used to send non-decimal values.
These values require a header (#B, #H or #Q) to identify the data format being sent. The
letter in the header can be upper or lower case. The <NRf> (numeric representation for-
mat) parameter type is used to send decimal values, and does not use a header. The follow-
ing examples show the proper parameter syntax for setting bits B5, B3, and B2:
#b101100 Binary format (<NDN> parameter type)
#h2C Hexadecimal format (<NDN> parameter type)
#q54 Octal format (<NDN> parameter type)
44 Decimal format (<NRf> parameter type)
Valid characters for the non-decimal parameter values are shown as follows:
<NDN> Format Valid Characters
Binary 1’s and 0’s
Hexadecimal 0 through 9 and A through F
Octal 0 through 7
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