73s1209f68im Maxim Integrated Products, Inc., 73s1209f68im Datasheet - Page 26

• Manufacturer Part Number: 73s1209f68im
• Description: Self-contained Pinpad, Smart Card Reader Ic Uart To Iso7816 / Emv Bridge Ic
• Manufacturer: Maxim Integrated Products, Inc.

MPU Clock Control Register (MPUCKCtl): 0xFFA1
The oscillator circuits are designed to connect directly to standard parallel resonant crystal in a Pierce
oscillator configuration. Each side of the crystal should include a 22pF capacitor to ground for both
oscillator circuits and a 1MΩ resistor is required across the 12MHz crystal.
The CPU clock is available as an output on pin CPUCLK (68-pin version only).
26
MPUCKCtl.7
MPUCKCtl.6
MPUCKCtl.5
MPUCKCtl.4
MPUCKCtl.3
MPUCKCtl.2
MPUCKCtl.1
MPUCKCtl.0
Note: The crystal should be placed as close as possible to the IC, and vias should be avoided.
Bit
MSB
–
Symbol
MDIV.5
MDIV.4
MDIV.3
MDIV.2
MDIV.1
MDIV.0
–
–
–
This value determines the ratio of the MPU master clock frequency to
the VCO frequency (MCLK) such that
MPUClk = MCLK/(2 * (MPUCKDiv(5:0) + 1)).
Do not use values of 0 or 1 for MPUCKDiv(n).
Default is 0Ch to set CPCLK = 3.6923MHz.
MDIV.5 MDIV.4 MDIV.3 MDIV.2 MDIV.1 MDIV.0
Table 13: The MPUCKCtl Register
22pF
Figure 4: Oscillator Circuit
73S1209F
12MHz
1MΩ
0x0C
Function
22pF
LSB
Rev. 1.2