+/** Enables the physical TPI interface on the target and enables access to the internal NVM controller.
+ *
+ * \return Boolean \c true if the TPI interface was enabled successfully, \c false otherwise
+ */
+bool TINYNVM_EnableTPI(void)
+{
+ /* Enable TPI programming mode with the attached target */
+ XPROGTarget_EnableTargetTPI();
+
+ /* Lower direction change guard time to 32 USART bits */
+ XPROGTarget_SendByte(TPI_CMD_SSTCS(TPI_REG_CTRL));
+ XPROGTarget_SendByte(0x02);
+
+ /* Enable access to the XPROG NVM bus by sending the documented NVM access key to the device */
+ XPROGTarget_SendByte(TPI_CMD_SKEY);
+ for (uint8_t i = sizeof(TPI_NVMENABLE_KEY); i > 0; i--)
+ XPROGTarget_SendByte(TPI_NVMENABLE_KEY[i - 1]);
+
+ /* Wait until the NVM bus becomes active */
+ return TINYNVM_WaitWhileNVMBusBusy();
+}
+
+/** Removes access to the target's NVM controller and physically disables the target's physical TPI interface. */
+void TINYNVM_DisableTPI(void)
+{
+ TINYNVM_WaitWhileNVMBusBusy();
+
+ do
+ {
+ /* Clear the NVMEN bit in the TPI STATUS register to disable TPI mode */
+ XPROGTarget_SendByte(TPI_CMD_SSTCS(TPI_REG_STATUS));
+ XPROGTarget_SendByte(0x00);
+
+ /* Read back the STATUS register, check to see if it took effect */
+ XPROGTarget_SendByte(TPI_CMD_SLDCS(TPI_REG_STATUS));
+ } while (XPROGTarget_ReceiveByte() != 0x00);
+
+ XPROGTarget_DisableTargetTPI();
+}
+