ADUC7025BCPZ32-RL7 AD [Analog Devices], ADUC7025BCPZ32-RL7 Datasheet - Page 52

• Manufacturer Part Number: ADUC7025BCPZ32-RL7
• Description: Precision Analog Microcontroller 12-bit Analog I/O, ARM7TDMI MCU
• Manufacturer: AD [Analog Devices]

ADuC7019/20/21/22/24/25/26/27
MMRs and Keys
The operating mode, clocking mode, and programmable clock
divider are controlled via two MMRs, PLLCON (see Table 32)
and POWCON (see Table 33). PLLCON controls the operating
mode of the clock system, while POWCON controls the core
clock frequency and the power-down mode.
To prevent accidental programming, a certain sequence (see
Table 34) has to be followed to write to the PLLCON and
POWCON registers.
PLLKEYx Registers
Name
PLLKEY1
PLLKEY2
PLLCON Register
Name
PLLCON
POWKEYx Registers
Name
POWKEY1
POWKEY2
POWCON Register
Name
POWCON
Table 32. PLLCON MMR Bit Designations
Bit
7:6
5
4:2
1:0
Value
00
01
10
11
Name
OSEL
MDCLK
Address
0xFFFF0410
0xFFFF0418
Address
0xFFFF0414
Address
0xFFFF0408
Address
0xFFFF0404
0xFFFF040C
Description
Reserved.
32 kHz PLL Input Selection. Set by
user to use the internal 32 kHz
oscillator. Set by default. Cleared by
user to use the external 32 kHz crystal.
Reserved.
Clocking Modes.
Reserved.
PLL. Default configuration.
Reserved.
External Clock on P0.7 Pin.
Default Value
0x0000
0x0000
Default Value
0x21
Default Value
0x0003
Default Value
0x0000
0x0000
Access
W
W
Access
R/W
Access
R/W
Access
W
W
Rev. A | Page 52 of 92
Table 33. POWCON MMR Bit Designations
Bit
7
6:4
3
2:0
Table 34. PLLCON and POWCON Write Sequence
PLLCON
PLLKEY1 = 0xAA
PLLCON = 0x01
PLLKEY2 = 0x55
Value
000
001
010
011
100
Others
000
001
010
011
100
101
110
111
PC
CD
Name
Description
Reserved.
Operating Modes.
Active Mode.
Pause Mode.
Nap.
Sleep Mode. IRQ0 to IRQ3 and
Timer2 can wake up the
ADuC7019/7020/7021/7022/7024/
7025/7026/7027.
Stop Mode. IRQ0 to IRQ3 can wake
up the ADuC7019/7020/7021/
7022/7024/7025/7026/7027.
Reserved.
Reserved.
CPU Clock Divider Bits.
41.78 MHz.
20.89 MHz.
10.44 MHz.
5.22 MHz.
2.61 MHz.
1.31 MHz.
653 kHz.
326 kHz.
POWCON
POWKEY1 = 0x01
POWCON = User Value
POWKEY2 = 0xF4