After adjusting the AVS voltage for VDD_CORE_L voltage domain, an IO Delay Recalibration Sequence must be followed to ensure device IO timings are met. The IO Delay Recalibration Sequence is as follows:
IO Delay Recalibration Sequence:
- Complete the AVS voltage change on the VDD_CORE_L voltage domain and ensure voltage has stabilized to the new AVS target voltage
- Unlock the registers used by this sequence as follows:
- Write 0x2FF1AC2B to register CTRL_CORE_MMR_LOCK_1 of the Control Module
- Write 0x6F361E05 to register CTRL_CORE_MMR_LOCK_5 of the Control Module
- Write 0x0000AAAA to register CONFIG_REG_8 of the IODELAYCONFIG Module
- Perform IO Delay Calibration
- Write register field CONFIG_REG_2[15:0] REFCLK_PERIOD of the IODELAYCONFIG Module with the L4_ICLK clock period in ps divided by 10 (or, equivalently, L3_ICLK clock period in ps divided by 5), then rounded down to the closest integer
- L4_ICLK = 133MHz requires a value of 0x2EF
- Write 1 to register field CONFIG_REG_0[0] CALIBRATION_START of the IODELAYCONFIG module to initiate the calibration.
- Poll register field CONFIG_REG_0[0] CALIBRATION_START for 0, indicating calibration is complete.
- Isolate the device IOs via the Isolation Sequence described in Section 18.4.6.1.7 Isolation Requirements
- Update the delay mechanism for each IO with new calibrated values:
- Write 1 to register field CONFIG_REG_0[1] ROM_READ of the IODELAYCONFIG module to initiate a reload of calibrated delay values for all IOs.
- Poll register field CONFIG_REG_0[1] ROM_READ for 0, indicating reload is complete.
- Configure the pad configuration register (CTRL_CORE_PAD_x) for each IO with the desired MUXMODE, DELAYMODE, and MODESELECT settings.
- Configure all required Manual IO Timing Modes as described in Section 18.4.6.1.6, Manual IO Timing Modes
- De-isolate the device IOs via the de-isolation sequence described in Section 18.4.6.1.7 Isolation Requirements
- Relock the registers used by this sequence:
- Write 0x1A1C8144 to register CTRL_CORE_MMR_LOCK_1
- Write 0x143F832C to register CTRL_CORE_MMR_LOCK_5
- Write 0x0000AAAB to register CONFIG_REG_8