ST have implemented the JTAG adaptor on the STM32L-DISCOVERY board. It’s very cheap board: ~12€ at . Detailed information is available via ST web page. On-board is a STM32L152RBT6 microcontroller featuring 128 KB Flash, 16 KB RAM, 4 KB EEPROM, in an LQFP64 package. On-board ST-Link/V2 is connected to “local” microcontroller. By removing two jumpers ST-LINK could be used to program external microcontroller.