I eventually solved this problem with some software and some hardware. A picture of the hardware is attached. It uses a TI Stellaris LM4F120 configured with two 3.3V UARTS, and a 3.3V GPIO to drive a 120V SSR (Solid State Relay). The LM4F120 can be powered directly from the 'SBR battery compartment pinout' (http://cms.diodenring.de/en/electronic/mikrocontroller/92-squeezebox).
One of the UARTs (UARTB) is connected to the SBR console UART in the battery compartment. The other UART (UARTA) is connected to the LM4F120 USB debug port. The software running on the LM4F120 copies characters from UARTB-RX to UARTA-TX, and characters from UARTA-RX to UARTB-TX. In this way, when the LM4F120 USB debug port is connected to a PC, the debug USB virtual serial port can be used to interact with the SBR console UART. Additionally the software watches for '\x7f' or '\x7e' characters on the SBR console UART. The software will assert the 3.3V GPIO if it senses '\x7f' on the SBR console UART, and resets the 3.3V GPIO if it sense a '\x7e'. Finally, some relatively straightforward changes in the SBR Jive implementation are required to send '\x7f' or '\x7e' at the right time. The picture shows the LM4F120 (red board) and the SSR alongside it. The grey cable houses the connection to the SBR battery connector. The black cables connect AC power plug via the SSR to power socket, which in turn is connected to the amplifier plug. +-------------------------------------------------------------------+ |Filename: SBR Trigger.jpg | |Download: http://forums.slimdevices.com/attachment.php?attachmentid=15054| +-------------------------------------------------------------------+ ------------------------------------------------------------------------ quietdragon's Profile: http://forums.slimdevices.com/member.php?userid=10412 View this thread: http://forums.slimdevices.com/showthread.php?t=97759 _______________________________________________ diy mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/diy
