From ac0203b42f74bfa6e9c267af179f9b8622412a70 Mon Sep 17 00:00:00 2001 From: hathach Date: Fri, 1 Nov 2019 10:13:19 +0700 Subject: [PATCH] update doc --- docs/porting.md | 2 ++ 1 file changed, 2 insertions(+) diff --git a/docs/porting.md b/docs/porting.md index 7fdeaeba7..a38ff0192 100644 --- a/docs/porting.md +++ b/docs/porting.md @@ -130,6 +130,8 @@ number and direction which usually determines where to write the buffer info. Th written to a specific location in memory and the peripheral is told the data is valid. (Maybe by writing a 1 to a register or setting a counter register to 0 for OUT or length for IN.) +The transmit buffer alignment is determined by `CFG_TUSB_MEM_ALIGN`. + One potential pitfall is that the buffer may be longer than the maximum endpoint size of one USB packet. Some peripherals can handle transmitting multiple USB packets for a provided buffer (like the SAMD21). Others (like the nRF52) may need each USB packet queued individually. To make this work you'll need to track