4.5.2.4.1 Writing the FCLKDIV register
Prior to issuing any flash and EEPROM program or erase command after a reset, the user
is required to write the FCLKDIV register to divide BUSCLK down to a target FCLK of
1MHz. The following table shows recommended values for the FDIV field based on
BUSCLK frequency.
Table 4-7. FDIV values for various BUSCLK frequencies
BUSCLK frequency
(MHz)
FDIV[5:0]
MAX
1.0
1.6
0x00
1.6
2.6
0x01
2.6
3.6
0x02
3.6
4.6
0x03
4.6
5.6
0x04
5.6
6.6
0x05
6.6
7.6
0x06
7.6
8.6
0x07
8.6
9.6
0x08
9.6
10.6
0x09
10.6
11.6
0x0A
11.6
12.6
0x0B
12.6
13.6
0x0C
13.6
14.6
0x0D
14.6
15.6
0x0E
15.6
16.6
0x0F
16.6
17.6
0x10
17.6
18.6
0x11
18.6
19.6
0x12
19.6
20.0
0x13
1. BUSCLK is greater than this value
2. BUSCLK is less than or equal to this value
CAUTION
Programming or erasing the flash and EEPROM memory
cannot be performed if the bus clock runs at less than 0.8 MHz.
Setting FCLKDIV[FDIV] too high can destroy the flash and
EEPROM memory due to overstress. Setting FCLKDIV[FDIV]
too low can result in incomplete programming or erasure of the
flash and EEPROM memory cells.
Chapter 4 Memory map
MC9S08PA4 Reference Manual, Rev. 5, 08/2017
NXP Semiconductors
61
Summary of Contents for MC9S08PA4
Page 1: ...MC9S08PA4 Reference Manual Supports MC9S08PA4 Document Number MC9S08PA4RM Rev 5 08 2017 ...
Page 2: ...MC9S08PA4 Reference Manual Rev 5 08 2017 2 NXP Semiconductors ...
Page 22: ...MC9S08PA4 Reference Manual Rev 5 08 2017 22 NXP Semiconductors ...
Page 28: ...System clock distribution MC9S08PA4 Reference Manual Rev 5 08 2017 28 NXP Semiconductors ...
Page 150: ...Port data registers MC9S08PA4 Reference Manual Rev 5 08 2017 150 NXP Semiconductors ...
Page 196: ...Human machine interfaces HMI MC9S08PA4 Reference Manual Rev 5 08 2017 196 NXP Semiconductors ...
Page 224: ...Instruction Set Summary MC9S08PA4 Reference Manual Rev 5 08 2017 224 NXP Semiconductors ...
Page 232: ...Functional Description MC9S08PA4 Reference Manual Rev 5 08 2017 232 NXP Semiconductors ...
Page 258: ...FTM Interrupts MC9S08PA4 Reference Manual Rev 5 08 2017 258 NXP Semiconductors ...
Page 294: ...Functional description MC9S08PA4 Reference Manual Rev 5 08 2017 294 NXP Semiconductors ...
Page 398: ...Resets MC9S08PA4 Reference Manual Rev 5 08 2017 398 NXP Semiconductors ...
Page 400: ...MC9S08PA4 Reference Manual Rev 5 08 2017 400 NXP Semiconductors ...