求证Si4438长数据包收发bug

只看该作者 · 2016-3-9 00:03

现在用si4438实现了固定长度包（小于64字节）发送没问题，但实际数据包大于64字节，所以想用长数据包收发功能，也就是FIFO中断，移植了官方的长数据包收发代码后测试发现两个问题：
1、FIFO即将空中断有时候失效。本该是FIFO即将空中断，但先来的是发送完成中断，这样的话永远进入不到即将空中断。导致数据不能完全发送。
2、FIFO即将空阈值设置不起作用。
后来实在没办法，参看了官方的文档，在官方是勘误手册上，明确提到了这两个bug是si4438 B1版本的bug，将在C2版本中修正。

我现在纳闷的是，在解决这个问题中，我百度了好久，都没发现网上有人提到这个bug，有提到用FIFO即将空中断实现大于64字节包发送的**，但是没提到芯片有bug，现在C2版的芯片不好买，不知其他人是怎样实现大于64字节包一次性发送的？

请高手赐教

只看该作者 · 2016-3-9 10:13

下面是官方勘误手册上对这两个bug的描述，我现在想知道的是怎么用变通的方法规避这个bug而不换芯片

FIFO_INFO command does not update TX_FIFO_ALMOST_EMPTY status properly
Description:  If the TX FIFO is reset by the FIFO_INFO command, the chip does not update the TX_FIFO_ALMOST_EMPTY status bit correctly. It gets updated only by the next TX FIFO fill that causes the TX_FIFO_ALMOST_EMPTY interrupt to occur later than expected.
Impact:       TX_FIFO_ALMOST_EMPTY interrupt occurs later than expected.
Workaround:  Write one dummy byte into the TX_FIFO to fire the TX_FIFO_ALMOST_EMPTY interrupt and reset the TX_FIFO again. A fix has been identified and will be included in the next revision of the device.
FIFO Threshold Limitations

Description: Threshold of TX_FIFO_ALMOST_EMPTY interrupt can only be set to as high as 58 bytes for reliable interrupt generation when the threshold is reached. If the payload length of the transmitted packet is less than 7 bytes, the user can rely on the PACKET_SENT interrupt which indicates the end of packet transmission. Threshold of RX_FIFO_ALMOST_FULL interrupt can only be set to as low as 12 bytes for reliable interrupt generation when the threshold is reached. If the payload length of the received packet is less than 12 bytes, the user can rely on the PACKET_RX interrupt which indicates the end of packet.
Impact:  User should not rely on FIFO threshold interrupts for greater than 58 bytes on the TX side and less than 12 bytes on the RX side.
Workaround:  Rely on PACKET_SENT and PACKET_RX interrupts for very small payload lengths as described above. A fix has been identified and will be included in the next revision of the device.