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Clarify 21489 UART TX Interrupt

Question asked by ahonkan on Sep 26, 2011
Latest reply on Oct 18, 2011 by ahonkan

Rev 0.3 of SHARC HW Ref Guide pg B7 suggests that I can generate a separate UART TX interrupt (0x15) and a UART RX interrupt (0x13).


I modified the 21489 Uart Loopback code to enable both the UART RX Buffer Full interrupt and UART TX Complete interrupt in UART0IER.  I assigned the UART RX and UART TX interrupts to P0, P1 in PICR0 and ran the 21489 Demo board code.  I noticed that every time I transmitted data, the UART RX isr would execute.  The UART TX isr never ran.


Can you please explain/clarify this behavior?  Does the 21489 support separate TX/RX isrs?  The only indication in the manual that this behavior may not be supported is on pg A-247 where it talks about legacy behavior.