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54 lines
1.3 KiB
54 lines
1.3 KiB
* ICP DAS LP-8841 SPI Controller for RTC |
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ICP DAS LP-8841 contains a DS-1302 RTC. RTC is connected to an IO |
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memory register, which acts as an SPI master device. |
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The device uses the standard MicroWire half-duplex transfer timing. |
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Master output is set on low clock and sensed by the RTC on the rising |
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edge. Master input is set by the RTC on the trailing edge and is sensed |
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by the master on low clock. |
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Required properties: |
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- #address-cells: should be 1 |
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- #size-cells: should be 0 |
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- compatible: should be "icpdas,lp8841-spi-rtc" |
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- reg: should provide IO memory address |
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Requirements to SPI slave nodes: |
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- There can be only one slave device. |
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- The spi slave node should claim the following flags which are |
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required by the spi controller. |
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- spi-3wire: The master itself has only 3 wire. It cannor work in |
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full duplex mode. |
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- spi-cs-high: DS-1302 has active high chip select line. The master |
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doesn't support active low. |
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- spi-lsb-first: DS-1302 requires least significant bit first |
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transfers. The master only support this type of bit ordering. |
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Example: |
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spi@901c { |
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#address-cells = <1>; |
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#size-cells = <0>; |
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compatible = "icpdas,lp8841-spi-rtc"; |
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reg = <0x901c 0x1>; |
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rtc@0 { |
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compatible = "maxim,ds1302"; |
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reg = <0>; |
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spi-max-frequency = <500000>; |
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spi-3wire; |
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spi-lsb-first; |
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spi-cs-high; |
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}; |
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};
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