Type C Macro Service Channel - NEC PD78212 User Manual

µ PD78214 Sub-Series
(2) Macro service channel configuration
There are two types of type C macro service channels, as shown in Fig. 12-26.
The timer macro service pointer (MPT) indicates a data buffer area in the 64K memory space from which data
is transferred to, or added to the contents of, the compare register for 8-bit timer/counter 1.
The data macro service pointer (MPD) indicates a data buffer area in the 64K memory space from which data
is transferred to the real-time output port.
The modulo register (MR) specifies the number of repetition patterns for ring control (if used).
The ring counter (RC) retains the steps in a pattern for ring control (if used). Usually, it is initialized with the
same value as for the modulo register.
The macro service counter (MSC) specifies the number of data transfers to occur.
The macro service channel, holding these pointers and counter, is located at addresses 0FE00H through
0FEFFH in the internal RAM space. The macro service channel is indicated by the channel pointer as shown
in Fig. 12-26. The channel pointer is set with the lower 8 bits of the address of the macro service channel.
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Fig. 12-26 Type C Macro Service Channel
(a) Without ring control
Lower address
Macro service counter
↑
(MSC)
Data macro service pointer,
low (MPDL)
Data macro service pointer,
high (MPDH)
Timer macro service pointer,
low (MPTL)
Timer macro service pointer,
high (MPTH)
Mode register
↓
Channel pointer
Higher address
Macro service channel
Macro service control word