Initialization Sequence - Samsung S5PC110 Manual

S5PC110_UM
5.3.2.1 Calibration Code for Closed-loop
In closed-loop mode, Calibration codes are used to control voltage level, while voltage values in open-loop mode.
Calibration code stands for critical path delay of ARM core. In S5PC110X, 14-th tap output of HPM has the nearly
same delay to the critical path of ARM core (when HPM clock ratio is equal to 1), which can be encoded to the
delay code 5'hE.

5.3.3 INITIALIZATION SEQUENCE

1. Initialize the index map & all other IEM & APC mapping values.
2. If IEM will use 'overdrive' level, then programs 'Max performance mapping index value' in IECDPCCR register
with proper values ( smaller than 3'b111)
3. Enables voltage scaling feature in the APC by setting 'APC_VDD_UD' bit in APC_CONTROL register as "1"
4. If IEM will use closed loop mode, then programs 'APC_HPM_EN' bit & 'APC_LOOP_MODE' bit in
APC_CONTROL register as "1"
5. Start IEM HW by setting 'iem_enable' bit in IEM_CONTROL register in power management unit as "1"
6. Start IEM control by setting "iec_enable" bit in IECDPCCR register as "1"
7. Now, the system is under the IEM control.
5 INTELLIGENT ENERGY MANAGEMENT
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