Chip Errata for the i.MX23 - Guy Carpenter

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5835 5835 5 V disconnections can cause large droops on the VDDIO and VDDD supply rails under certain operating conditions Description: When 5 V is disconnected, the DCDC does not switch its input from the VDD4P2 source to the battery quickly enough to prevent the DCDC output from drooping under heavy loads. One condition that exhibits the problem is a disconnect from 5 V with a 3.5-V battery voltage and a ~250-mA load on VDDIO. Workaround: To prevent a significant dip, the VDD4P2 must switch off as soon as possible when 5 V is lost to alert the DCDC to use battery power. To do this, configure the VDD5V_DROOP interrupt as an FIQ and set the droop interrupt threshold to a voltage level above the VBUSVALID threshold. Inside the VDD5V_DROOP handler, clear the ENABLE_DCDC and ENABLE_4P2 bits in the HW_POWER_DCDC4P2 register. Chip Errata for the i.MX23, Rev. 2 28 Freescale Semiconductor
5837 Setting the ENABLE_DCDC bit in the HW_POWER_DCDC4P2 or HW_POWER_5VCTRL registers can result in false brownout detection Description: When the ENABLE_DCDC bit in HW_POWER_DCDC4P2 is set, a glitch is propagated through the brownout comparators. If the glitch is sufficiently large, it can cause a false brownout detection. The VDDD, VDDA, VDDIO, and VBUSVALID comparators are all susceptible to the glitch. Workaround: The sequence below is needed to work around this issue prior to setting the ENABLE_DCDC bit in HW_POWER_DCDC4P2: 1. Disable the power rail brownout interrupts (clear HW_POWER_CTRL VDDA, VDDD, VDDIO ENIRQ bits). 2. Set the HW_POWER_5VCTRL PWRUP_VBUS_CMPS bit (may already be set). 3. Set the HW_POWER_5VCTRL VBUSVALID_5VDETECT bit to 0. 4. Set the HW_POWER_5VCTRL VBUSVALID_TRSH to 0x0 (2.9V). 5. Disable VBUSDROOP status and interrupts (clear VDD5V_DROOP_IRQ). 6. Set the ENABLE_DCDC bit in HW_POWER_DCDC4P2. 7. Wait 100 μs. 8. Check VBUSVALID_IRQ bit. If it is set, then set and clear the PWD_CHARGE_4P2 bit to repower on the 4P2 regulator because it is automatically shut off on a VBUSVALID false condition. It may be helpful to ramp up the CHARGE_4P2_ILIMIT value at this point to gradually draw power from 5 V rail. If HW_POWER_5VCTRL ENABLE_DCDC is already set, the DCDC will we sourcing charge from 4P2 as soon as PWD_CHARGE_4P2 is toggled. 9. Clear VBUSDROOP, VBUSVALID, and the output rails IRQ bits as needed. 10. Restore the output rail ENIRQ bits, the VBUSVALID_THRSH level, VBUSVALID_DETECT value, VBUSVALID ENIRQ, and VBUSDROOP ENIRQ to their original values. The sequence below is needed to work-around this issue prior to setting the ENABLE_DCDC bit in HW_POWER_5VCTRL. Note that the below workaround assumes the usual requirements for setting the HW_POWER_5VCTRL ENABLE_DCDC bit are met (that is, the hardware and/or software battery brownout protection mechanism is enabled to properly protect the system against the DCDC sourcing from the battery if the voltage if the battery voltage is too low.). 1. Disable the power rail brownout interrupts (clear HW_POWER_CTRL VDDA, VDDD, VDDIO ENIRQ bits). 2. Set the HW_POWER_5VCTRL PWRUP_VBUS_CMPS bit (may already be set). 3. Set the HW_POWER_5VCTRL VBUSVALID_5VDETECT bit to 1. 4. Set the HW_POWER_5VCTRL VBUSVALID_TRSH to 0x0 (2.9V). Chip Errata for the i.MX23, Rev. 2 Freescale Semiconductor 29 5837
Page 1 and 2: Freescale Semiconductor Errata Chip
Page 3 and 4: 2229 Insufficient SD/MMC read delay
Page 5 and 6: 2727 I2C 9th Clock Pulse (ACK) not
Page 7 and 8: 2747 Undetectable data corruption c
Page 9 and 10: 2749 USB: Port change interrupt not
Page 11 and 12: 2765 Chip locks up when switching t
Page 13 and 14: 2786 JTAG crash when HCLK is less t
Page 15 and 16: 2811 Unreliability of VDD5V_GT_VDDI
Page 17 and 18: 2814 The DCDC converters inadverten
Page 19 and 20: 2816 The PWDN_5VBRNOUT functionalit
Page 21 and 22: 2836 APBH/APBX do not flush out the
Page 23 and 24: 2854 The DCDC fails to shut down wh
Page 25 and 26: Workaround: Postpone freeing the cu
Page 27: 4733 SD Boot does not support MMC w
Page 31 and 32: 2349 The DAC DMA halts unexpectedly

Chip Errata for the i.MX23 - Guy Carpenter

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