Renesas 4514 - Manual (Page 57)

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HARDWARE
4513/4514 Group User’s Manual
FUNCTION BLOCK OPERATIONS
Fig. 28 Setting registers
0 ✕ ✕ 1
(Bit 3) (Bit 0)
A-D control register Q2
A IN4 function selected
A-D conversion mode
A-D control register Q1
A IN4 pin selected
✕ 1 0 0
(Bit 3) (Bit 0)
✕ : Set an arbitrary value
(8) A-D conversion timing chart
Figure 27 shows the A-D conversion timing chart.
Fig. 27 A-D conversion timing chart
(9) How to use A-D conversion
How to use A-D conversion is explained using as example in which
the analog input from P4 0 /A IN4 pin is A-D conver ted, and the high-
order 4 bits of the converted data are stored in address M(Z, X, Y)
= (0, 0, 0), the middle-order 4 bits in address M(Z, X, Y) = (0, 0, 1),
and the low-order 2 bits in address M(Z, X, Y) = (0, 0, 2) of RAM.
The A-D interrupt is not used in this example.
➀ After selecting the A IN4 pin function with the bit 0 of the register
Q2, select A IN4 pin and A-D conversion mode with the register
Q1 (refer to Figure 28).
➁ Execute the ADST instruction and start A-D conversion.
➂ Examine the state of ADF flag with the SNZAD instruction to de-
termine the end of A-D conversion.
➃ Transfer the low-order 2 bits of converted data to the high-order
2 bits of register A (TALA instruction).
➄ Transfer the contents of register A to M (Z, X, Y) = (0, 0, 2).
➅ Transfer the high-order 8 bits of converted data to registers A
and B (TABAD instruction).
➆ Transfer the contents of register A to M (Z, X, Y) = (0, 0, 1).
➇ Transfer the contents of register B to register A, and then, store
into M(Z, X, Y) = (0, 0, 0).
ADST instruction
A-D conversion
completion flag (ADF)
62 machine cycles
DAC operation signal