TI中文支持网CC2541 协议栈版本1.4.1 串口接收 ISR模式下 超时可以用，收到一段连续的数据，调用一次callback函数。DMA模式下，每收到一个字节调用一次callback，超时没有用。
Viki Shi：
建议下载并使用1.4.2版本的协议栈，该版本更新了1.4.1 的串口DMA接收不连续问题
-Fixed CC254x UART DMA reception discontinuity
user1354758：
回复 Viki Shi:
Texas Instruments, Inc. CC2540/41 Bluetooth low energy Software Development Kit Release Notes BLE-Stack(tm) Version 1.4.1 May 21, 2015 Notices: – This version of the Texas Instruments BLE-Stack and software is a maintenance update to the v1.4.0 release. It contains several bug fixes and enhancements. – The BLE protocol stack, including both the controller and host, was completely retested for v1.4.1. – All Sample Applications in the SDK ported and verified for v1.4.1 – Default SDK installation path is C:\Texas Instruments\BLE-CC254x-1.4.1.xxxxx\ where "xxxxx' is the SDK build revision number. – For guidance on how to port existing v1.4.0 projects to v1.4.1, refer to the "Additional Resources" section below. Changes and minor enhancements: – All projects have been migrated from IAR v8.20.2 to IAR 9.10.3. In order to build all projects, be sure to upgrade to IAR v9.10.3. – Smarter handling of connection parameter updates with multiple connections – GAPRole_SetParameter(GAPROLE_ADVERT_DATA) changes the advertising data – Allows removal of Service Changed Characteristic – HAL components set to TRUE if not defined – Added HCI Vendor Specific Guide revision history – Several bug fixes. Bug Fixes: – Fix for RSSI value does not change in V1.4 stack – Fix for Number HCI Commands parameter not updated in Command Complete Event – Fixed CC254x UART DMA reception discontinuity 这个是1.4.1的协议栈解决的bug，实际上没有解决，我对比了1.4.1和1.4.2的_hal_uart_dma.c文件，感觉差别不大
