M32C8A Datasheet, PDF (293/372 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M32C/80 Series

M32C/8A Group
21. X/Y Conversion
21. X/Y Conversion
The X/Y conversion rotates a 16 x 16 matrix data by 90 degrees and also inverts high-order bits and low-order bits of a
16-bit data. Figure 21.1 shows the XYC register.
The 16-bit XiR register (i = 0 to 15) and 16-bit YjR register (j = 0 to 15) are allocated to the same address. The XiR
register is a write-only register, while the YjR register is a read-only register. Access registers XiR and YjR from an
even address in 16-bit units. Performance cannot be guaranteed if registers XiR and YjR are accessed in 8-bit units.
X/Y Control Register
b7 b6 b5 b4 b3 b2 b1 b0
Symbol
XYC
Address
02E0h
Bit
Symbol
Bit Name
XYC0
Read mode set bit
Function
0: Data converted
1: Data not converted
XYC1
Write mode set bit
0: Bit alignment not converted
1: Bit alignment converted
−
(b7-b2)
Unimplemented.
Write 0. Read as undefined value.
After Reset
XXXX XX00b
RW
RW
RW
−
Figure 21.1 XYC Register
The XYC0 bit in the XYC register determines how to read the YjR register.
When setting the XYC0 bit to 0 (data converted) and reading the YjR register, all the bits j in registers X0R to X15R
can be read.
For example, bit 0 in the X0R register can be read when reading bit 0 in the Y0R register, bit 0 in the X1R register
when reading bit 1 in the Y0R register..., bit 0 in the X14R register when reading bit 14 in the Y0R register, and bit 0 in
the X15R register when reading bit 15 in the Y0R register.
Figure 21.2 shows a conversion table when the XYC0 bit is set to 0. Figure 21.3 shows an example of the X/Y
conversion.
Rev.1.00 Jul 15, 2007 Page 276 of 352
REJ09B0385-0100