RL78/D1A User's Manual: Hardware - Renesas

Under development
Preliminary document
Specifications in this document are tentative and subject to change.
RL78/D1A CHAPTER 5 CLOCK GENERATOR
(9) High-speed on-chip oscillator trimming register (HIOTRM)
This register is used to adjust the accuracy of the high-speed on-chip oscillator.
With self-measurement of the high-speed on-chip oscillator frequency via a timer using high-accuracy external clock
input (timer array unit), and so on, the accuracy can be adjusted.
The HIOTRM register can be set by an 8-bit memory manipulation instruction.
Reset signal generation clears this register to default value (undefined).
Caution The frequency will vary if the temperature and VDD pin voltage change after accuracy
adjustment. When the temperature and VDD voltage change, accuracy adjustment must be
executed regularly or before the frequency accuracy is required.
Figure 5-11. Format of High-speed on-chip oscillator Trimming Register (HIOTRM)
Address: F00A0H After reset: undefined R/W
Symbol 7 6 5 4 3 2 1 0
HIOTRM 0 0 HIOTRM5 HIOTRM4 HIOTRM3 HIOTRM2 HIOTRM1 HIOTRM0
HIOTRM5 HIOTRM4 HIOTRM3 HIOTRM2 HIOTRM1 HIOTRM0
High-speed on-chip
oscillator
0 0 0 0 0 0 Minimum speed
0 0 0 0 0 1
0 0 0 0 1 0
0 0 0 0 1 1
0 0 0 1 0 0
1 1 1 1 1 0
1 1 1 1 1 1 Maximum speed
R01UH0317EJ0004 Rev. 0.04 286
Feb. 22, 2013