ML7344C datasheet(49/154 Pages) LAPIS

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FEDL7344C/E/J-05

ML7344C/E/J

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(2) RX_FIFO usage notification function

This function is to notify remaining RX_FIFO by using interrupt (SINTN) to the MCU. If RX_FIFO usage

(un-read data in RX_FIFO) exceed Full level threshold defined by [RXFIFO_THRH: B0 0x19] register,

interrupt will generate as FIFO-Full interrupt (INT[5] group1). After MCU read RX data from RX_FIFO,

un-read amount become smaller than Empty level threshold defined by [RXFIFO_THRL: B0 0x1A] register,

interrupt will generated as FIFO-Empty (INT[4] group1). Interrupt signal (SINTN) can be output from GPIO*

or EXT_CLK.

For output setting, please refer to [GPIO1_CTRL: B0 0x4E], [GPIO1_CTRL: B0 0x4F], [GPIO2_CTRL: B0

0x50], [GPIO3_CTRL: B0 0x51], [EXTCLK_CTRL: B0 0x52] registers.

[Reference Sequence]:

Set Full level threshold and Empy level threshold..Each threshold should set as RXFIFO_THRH[5:0]

([RXFIFO_THRH:B0 0x19(5-0)]) > RXFIFO_THRL[5:0] ([RXFIFO_THRL:B0 0x1A(5-0)]). And

enabling Full level threshold by RXFIFO_THRH_EN([RXFIFO_THRH:B0 0x19(7)=0b1.

After issuing RX_ON, wait FIFO-Full interrupt (INT[5] group1) generation.

After FIFO-Full interrupt is generated, Clear the interupt. Then disabling Full level threshold

(RXFIFO_THRH_EN=

0b0)

and

enabling

Empty

level

threshold

(RXFIFO_THRL_EN

([RXFIFO_THRL:B0 0x1A(7)])=0b1). And start reading RX data from RX_FIFO [RD_FIFO:B0

0x7F].

After FIFO-Empty interrupt (INT[4] group1) is generated, Clear the interupt. Then disabling Empty

level threshold (TXFIFO_THRL_EN=0b0) and enabling Full level threshold (TXFIFO_THRH_

EN=0b1). Then resume writing TX data to the TX_FIFO until next FIFO-Full interrupt occurs.

Repeat 3.-4. until completion of RX data read out.

NOTE:

When skip disabling threshold level at sequece 3. or 4., depending on RX data write (PHY block) and

RX_FIFO read timing through SPI, in the middle of RX_FIFO reading, unwiilling FIFO-Full interrupt or

FIFO-Empty interrupt may occurs.

Empty level

(Example 0x0F)

Full level

(Example 0x2E)

0x3F

Generate interrupt

when un-read data

amount is less than

Empty level after

read RX data from

RX FIFO.

[FIFO usage]

Time

Full level

Empty level

RX data amount

RX_FIFO usage

transition

0x0F

0x2E

SINTN signal

Clear interrupt

0x00

Generate interrupt

when RX Data

exceed Full level

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