PXS20RM Datasheet, PDF (1145/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

Chapter 35
Oscillators
This chapter describes the following modules on this device:
• Internal RC oscillator (IRCOSC)
• External oscillator (XOSC)
Oscillators
35.1 IRCOSC 16 MHz internal RC oscillator
The internal RC oscillator has a nominal frequency of 16 MHz. The major features of the oscillator are:
• Glitch-free oscillation
• 6-bit trimming
The value of resistor is trimmed back using trim RCTRIM[5:0] of the RC_CTL register, so that the output
clock frequency is never out of ±1% of 16 MHz over the process. After the oscillator is trimmed within
this range using Trim Bits, the variation over the voltage and temperature is ±5%.
After power on reset, the trimming bits are provided by the flash options.
Table 35-1. RC Digital Interface Registers - base address 0xC3FE_0060
Register Name
Address Offset
Reset Value
RC_CTL
0x00
0x0000
Offset 0x0
Access: User read
Supervisor read/write
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15
R0 0 0 0 0 0 0 0 0 0
W
RCTRIM
RESET: ₀
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
R0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
W
RESET: ₀
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
= Unimplemented or reserved
Figure 35-1. RC Control Register (RC_CTL)
Freescale Semiconductor
PXS20 Microcontroller Reference Manual, Rev. 1
35-1