mayhem-firmware/firmware/common/jtag.hpp
2015-07-08 08:39:24 -07:00

135 lines
2.8 KiB
C++

/*
* Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
*
* This file is part of PortaPack.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifndef __JTAG_H__
#define __JTAG_H__
#include <cstdint>
#include <cstddef>
#include <bitset>
namespace jtag {
class Target {
public:
using bit_t = uint_fast8_t;
virtual ~Target() {
}
virtual void delay(const size_t n) = 0;
virtual jtag::Target::bit_t clock(
const jtag::Target::bit_t tms_value,
const jtag::Target::bit_t tdi_value
) = 0;
};
class JTAG {
public:
constexpr JTAG(
Target& target
) : target(target)
{
}
void reset() {
/* ??? -> Test-Logic-Reset */
for(size_t i=0; i<8; i++) {
target.clock(1, 0);
}
}
void run_test_idle() {
/* Test-Logic-Reset -> Run-Test/Idle */
target.clock(0, 0);
}
void runtest_tck(const size_t count) {
target.delay(count);
}
uint32_t shift_ir(const size_t count, const uint32_t value) {
/* Run-Test/Idle -> Select-DR-Scan -> Select-IR-Scan */
target.clock(1, 0);
target.clock(1, 0);
/* Scan -> Capture -> Shift */
target.clock(0, 0);
target.clock(0, 0);
const auto result = shift(count, value);
/* Exit1 -> Update */
target.clock(1, 0);
/* Update -> Run-Test/Idle */
target.clock(0, 0);
return result;
}
uint32_t shift_dr(const size_t count, const uint32_t value) {
/* Run-Test/Idle -> Select-DR-Scan */
target.clock(1, 0);
/* Scan -> Capture -> Shift */
target.clock(0, 0);
target.clock(0, 0);
const auto result = shift(count, value);
/* Exit1 -> Update */
target.clock(1, 0);
/* Update -> Run-Test/Idle */
target.clock(0, 0);
return result;
}
template<size_t N>
void shift_dr(std::bitset<N>& bits) {
/* Run-Test/Idle -> Select-DR-Scan */
target.clock(1, 0);
/* Scan -> Capture -> Shift */
target.clock(0, 0);
target.clock(0, 0);
for(size_t i=0; i<bits.size(); i++) {
bits[i] = target.clock(
(i == (bits.size() - 1)) ? 1 : 0,
bits[i]
);
}
/* Exit1 -> Update */
target.clock(1, 0);
/* Update -> Run-Test/Idle */
target.clock(0, 0);
}
private:
Target& target;
uint32_t shift(const size_t count, uint32_t value);
};
} /* namespace jtag */
#endif/*__JTAG_H__*/