Visible to Intel only — GUID: eub1481130106229
Ixiasoft
Visible to Intel only — GUID: eub1481130106229
Ixiasoft
16.5.2.1. Power-On Reset Sequence
- Before enabling power to the card, confirm that the voltage setting to the voltage regulator is correct. †
- Enable power to the card by setting the power enable bit (power_enable) in the power enable register (pwren) to 1. Wait for the power ramp‑up time before proceeding to the next step.†
- Set the interrupt masks by resetting the appropriate bits to 0 in the intmask register.†
- Set the int_enable bit of the ctrl register to 1.†
Note: Intel recommends that you write 0xFFFFFFFF to the rintsts register to clear any pending interrupts before setting the int_enable bit to 1.†
- Discover the card stack according to the card type. For discovery, you must restrict the clock frequency to 400 kHz in accordance with SD/MMC/CE‑ATA standards. For more information, refer to Enumerated Card Stack.†
- Set the clock source assignments. Set the card frequency using the clkdiv and clksrc registers of the controller. For more information, refer to Clock Setup.†
- The following common registers and fields can be set during initialization process:†
- The response timeout field (response_timeout) of the tmout register. A typical value is 0x40.†
- The data timeout field (data_timeout) of the tmout register, highest of the following:†
-
10 * NAC †
NAC = card device total access time†
= 10 * ((TAAC * FOP) + (100 * NSAC))†
where:†
TAAC = Time‑dependent factor of the data access time†
FOP = The card clock frequency used for the card operation†
NSAC = Worst‑case clock rate‑dependent factor of the data access time†
-
Host FIFO buffer latency†
On read: Time elapsed before host starts reading from a full FIFO buffer†
On write: Time elapsed before host starts writing to an empty FIFO buffer†
-
- Debounce counter register (debnce). A typical debounce value is 25 ms.†
- TX watermark field (tx_wmark) of the FIFO threshold watermark register (fifoth). Typically, the threshold value is set to 512, which is half the FIFO buffer depth.†
- RX watermark field (rx_wmark) of the fifoth register. Typically, the threshold value is set to 511.†
These registers do not need to be changed with every SD/MMC/CE‑ATA command. Set them to a typical value according to the SD/MMC/CE‑ATA specifications.