JTAG interface

IR

The IR is 8 bits long. The following instructions exist:

IR	Instruction	Register
`00000000`	`EXTEST`	`BOUNDARY`
`00000001`	`IDCODE`	`IDCODE`
`00000010`	`INTEST`	`BOUNDARY`
`00000011`	`SAMPLE`	`BOUNDARY`
`00010001`	`TEST_ENABLE`	`DATAREG`
`00010010`	`BULKPROG`	`DATAREG`
`00010011`	`MVERIFY`	`DATAREG`
`00010100`	`ERASE_ALL`	`DATAREG`
`00010101`	`TEST_DISABLE`	`DATAREG`
`00010110`	`STCTEST`	`STC`
`11000000`	`ISC_DISABLE`	`DATAREG`
`11100000`	`ISC_NOOP`	`BYPASS`
`11100100`	`ISC_ENABLE_OTF`	`DATAREG`
`11100110`	`ISC_SRAM_WRITE`	`DATAREG`
`11100111`	`ISC_SRAM_READ`	`DATAREG`
`11101000`	`ISC_ENABLE`	`DATAREG`
`11101001`	`ISC_ENABLE_CLAMP`	`DATAREG`
`11101010`	`ISC_PROGRAM`	`DATAREG`
`11101101`	`ISC_ERASE`	`DATAREG`
`11101110`	`ISC_READ`	`DATAREG`
`11110000`	`ISC_INIT`	`DATAREG`
`11111010`	`CLAMP`	`BYPASS`
`11111100`	`HIGHZ`	`BYPASS`
`11111101`	`USERCODE`	`USERCODE`
`11111111`	`BYPASS`	`BYPASS`

The IR status is:

bit 0: const 1
bit 1: const 0
bits 2-7: ???

TODO: completely unverified from BSDL; DR assignments are suspect

Boundary scan register

TODO: write me

ISP instructions

TODO: write me

Programming sequence

TODO: write me