Database schema¶
The ATF15xx chip database is the ultimate artefact produced by Project Bureau. Most importantly, it assigns a symbolic name to each known fuse or group of fuses and a symbolic value to each known pattern these fuses can take. Aside from that, it establishes relationships between basic elements: macrocells and logic blocks, macrocells and pins, pads and special functions.
The canonical form of the chip database distributed by the project is its JSON serialization. A machine-readable JSON schema that describes the chip database structure is also available. The rest of this document contains a human-readable description of the chip database format.
General structure¶
The chip database contains two kinds of entries: nodes and leaves. A node is a container (object or array) that may include other nodes and leaves. A leaf is an arbitrary data structure describing a feature of the device, e.g. the location of a fuse in a JED file plus its symbolic description. The chip database only uses a small amount of different leaf structures, which are described below.
Reference leaf¶
Example: "M0".
The reference leaf links a single node to the node it’s in. It is a string containing the name of the linked node.
Sequence leaf¶
Example: ["MC1", "MC2"].
The sequence leaf links an ordered set of nodes to the node it’s in. It is an array of references.
Mapping leaf¶
Example: {"M1": "42", "M2": "43"}.
The mapping leaf describes a one-to-one correspondence between nodes. It is an object containing references where the keys are also references.
Range leaf¶
Example: [100, 200].
The range leaf describes a contiguous sequence of fuse indexes. It is an array containing two integers: the inclusive lower bound and the exclusive upper bound.
Xpoints leaf¶
Example: {"UIM2_P": 16, "UIM2_N": 17}.
The crosspoints leaf describes a one-to-one correspondence between networks and fuse offsets. It is an object containing integer fuse offsets where the keys are network names. (This leaf is only used once, to describe product term layout.)
Option leaf¶
Example: {"fuses": [123, 124], "values": {"high_z": 3, "pull_up": 2, "pull_down": 0}}.
The option leaf assigns symbolic names to combinations of fuse values, and describes a configurable device feature. It is an object with two keys, fuses and values.
The fuses key is an array of fuse indexes that unambiguously maps fuse combinations to integers–the value of first specified fuse is the least significant bit in the binary notation.
The values key is an object containing symbolic names for known fuse combinations. All names point to unique fuse combiantions, though not every possible fuse combination may have a name assigned to it.
Node database¶
The root node is a map from device names (e.g. ATF1502AS) to device specifications. The rest of this page is written in the context of a single device specification.
For device_name, device in database:
Node device['pins']¶
This node is a map from packages (e.g. TQFP44) to pinouts.
For package, pinout in device['pins']:
Mapping pinout¶
This mapping relates pads (e.g. C2, M1) to package pins (e.g. 40, 42).
Mapping device['specials']¶
This mapping relates special functions (e.g. CLK1, TMS) to pads (e.g. C1, M9).
Node device['blocks']¶
This node is a map from block names (e.g. A) to block specifications.
For block_name, block in device['blocks']:
Sequence block['macrocells']¶
This sequence contains the names of macrocells in the logic block.
Sequence block['switches']¶
This sequence contains the names of interconnect switches in the logic block.
Xpoints block['pterm_points']¶
This leaf relates block-local networks to product term fuse offsets. All macrocells in this block share an identical layout of product term fuses. To find a fuse that would include a specific network in a product term, add the index of the first fuse in the product term to the offset corresponding to the network in this leaf.
Node device['macrocells']¶
This node is a map from macrocell names (e.g. MC1) to macrocell specifications.
For macrocell_name, macrocell in device['macrocells']:
Reference macrocell['block']¶
This reference links the macrocell to the block that contains the macrocell.
Reference macrocell['pad']¶
This reference links the macrocell to the name of the pad connected to the macrocell. The pad connected to a macrocell MCx is always called Mx; this leaf is provided for convenience.
Node macrocell['pterm_ranges']¶
This node is a map from product term names (which are always PT1, PT2, PT3, PT4, PT5) to product term fuse ranges.
For pterm_name, pterm_range in macrocell['pterm_ranges']:
Range pterm_range¶
This range contains the product term fuses. The functions of the individual fuses are specified in the block that contains the macrocell.
Option macrocell['pt1_mux']¶
This option configures whether the PT1 product term feeds the sum term or the special function (logic foldback node, and in rare cases XOR term).
Option macrocell['pt2_mux']¶
This option configures whether the PT2 product term feeds the sum term or the special function (XOR term).
Option macrocell['pt3_mux']¶
This option configures whether the PT3 product term feeds the sum term or the special function (asynchronous reset).
Option macrocell['gclr_mux']¶
This option configures whether the GCLR global network will reset the storage element of the macrocell.
Option macrocell['pt4_mux']¶
This option configures whether the PT4 product term feeds the sum term or the special function (clock or clock enable).
Option macrocell['pt4_func']¶
This option configures whether, if it drives a special function, the PT4 product term clocks the storage element of the macrocell, or enables the storage element driven by a global clock network.
Option macrocell['gclk_mux']¶
This option configures which GCLKx global network will clock of the storage element of the macrocell when the macrocell is clocked by a global network.
Option macrocell['pt5_mux']¶
This option configures whether the PT5 product term feeds the sum term or the special function (asynchronous set or output enable).
Option macrocell['pt5_func']¶
This option configures whether, if it drives a special function, the PT5 product term presets the storage element of the macrocell, or enables the output buffer.
Option macrocell['xor_a_mux']¶
This option configures whether the 1st input of the XOR term is driven by the sum term or the PT2 product term.
Warning
This option and cas_mux cannot be simultaneously set to arbitrary values because they share a fuse.
Option macrocell['xor_b_mux']¶
This option configures whether the 2nd input of the XOR term is driven by the output of the storage element, the inverse of the PT1 product term, the inverse of the PT2 product term, or a constant low.
Option macrocell['cas_mux']¶
This option configures whether the sum term feeds the XOR term or the cascade output of the macrocell.
Warning
This option and xor_a_mux cannot be simultaneously set to arbitrary values because they share a fuse.
Option macrocell['xor_invert']¶
This option configures whether the output of the XOR term is inverted.
Warning
This option and reset cannot be simultaneously set to arbitrary values because they share a fuse.
Option macrocell['d_mux']¶
This option configures whether the storage element samples the combinatorial function or the fast input.
Option macrocell['dfast_mux']¶
This option configures whether the pad or the PT2 product term is selected as the fast input.
Warning
This option and o_mux cannot be simultaneously set to arbitrary values because they share a fuse.
Option macrocell['storage']¶
This option configures whether the storage element functions as a D-flip-flop or a D-latch. On BE-series devices with 64 macrocells or more, it can also configure the storage element as a T-flip-flop.
Option macrocell['reset']¶
This option configures the power-on reset value of the storage element.
Warning
This option and xor_invert cannot be simultaneously set to arbitrary values because they share a fuse.
Option macrocell['fb_mux']¶
This option configures whether the feedback signal MCx_FB is driven by the combinatorial function or the storage element.
Option macrocell['o_mux']¶
This option configures whether the output buffer is driven by the combinatorial function or the storage element.
Warning
This option and dfast_mux cannot be simultaneously set to arbitrary values because they share a fuse.
Option macrocell['oe_mux']¶
This option configures whether the output buffer is enabled by one of the GOEx global networks, by the PT5 product term, or is always disabled.
Option macrocell['slew_rate']¶
This option configures the slew rate of the output buffer of the macrocell.
Option macrocell['output_driver']¶
This option configures the output buffer of the macrocell as push-pull or open-collector.
Option macrocell['pt_power']¶
Portability
This option is present only in AS-series devices.
This option configures whether the macrocell’s product terms are active or disabled to save power.
Option macrocell['low_power']¶
Portability
This option is present only in AS-series devices.
This option configures whether the macrocell operates at reduced power and reduced switching speed.
Option macrocell['termination']¶
Portability
This option is present only in BE-series devices.
This option configures the termination of the macrocell pin.
Option macrocell['hysteresis']¶
Portability
This option is present only in BE-series devices.
This option configures whether the input buffer of the macrocell has hysteresis.
Option macrocell['io_standard']¶
Portability
This option is present only in BE-series devices with 64 macrocells or more. This option is absent on VREFx pins.
This option configures whether the input buffer of the macrocell follows the LVCMOS or SSTL signaling standard.
Node device['switches']¶
This node is a map from switch names (e.g. UIM1) to switch specifications.
For switch_name, switch in device['switches']:
Reference switch['block']¶
This reference links the switch to the block that contains the switch.
Option switch['mux']¶
This option configures the network selected by the switch.
Node device['globals']¶
This node is a map from global network names (e.g. GCLR, GCLK1) to global network specifications.
For switch_name, switch in device['globals']:
Option switch['mux']¶
Note
This option is absent for the GCLR global network.
This option configures the network selected by the switch.
Option switch['invert']¶
This option configures the output buffer of the switch as inverting or non-inverting.
Node device['config']['pins']¶
This node is a map from special pins (e.g. CLR, TMS) to I/O buffer options.
For special, config in device['config']['pins']:
Option config['standby_wakeup']¶
Portability
This option is present only in AS-series devices for the CLKx pins.
This option configures whether transitions on a CLKx pin will wake up the device from a low-power standby mode.
Option config['termination']¶
Portability
On AS-series devices, this option is present only for the JTAG TMS and TDI pins.
This option configures the termination of the special pin.
Option config['hysteresis']¶
Portability
This option is present only in BE-series devices for the CLK1, CLK2, OE1, and CLR pins.
This option configures whether the input buffer of the special pin has hysteresis.
Node device['config']¶
This node enumerates device-wide options.
Let config be device['config']:
Option config['arming_switch']¶
This option configures the arming switch.
Option config['read_protection']¶
This option configures the read protection.
Option config['jtag_pin_func']¶
This option configures the special function of JTAG pins.
Option config['pd1_pin_func']¶
This option configures the special function of the PD1 pin.
Option config['pd2_pin_func']¶
This option configures the special function of the PD2 pin.
Option config['termination']¶
Portability
This option is present only in AS-series devices.
This option configures the termination of every macrocell pin.
Option config['reset_hysteresis']¶
Portability
This option is present only in AS-series devices.
This option configures the behavior of the power-on reset circuitry when VCC is close to VRST.
Node device['user']¶
This node is an array of user signature byte specifications.
For user_byte in device['user']:
Node device['ranges']¶
In ATF15xx fuse maps, fuses are mostly grouped into contiguous ranges based on their function. This node enumerates the known fuse ranges. These ranges are primarily useful to the fuzzing machinery itself.
Let ranges be device['ranges']:
Range ranges['pterms']¶
This range is occupied by product term fuses. It is only useful to the fuzzing machinery itself.
Range ranges['macrocells']¶
This range is occupied by macrocell options. It is only useful to the fuzzing machinery itself.
Range ranges['uim_muxes']¶
This range is occupied by interconnect muxes. It is only useful to the fuzzing machinery itself.
Range ranges['goe_muxes']¶
This range is occupied by global output enable muxes. It is only useful to the fuzzing machinery itself.
Range ranges['config']¶
This range is occupied by global clock muxes, global network inverters, special function options, pin termination options, and other device-wide configuration options. It is only useful to the fuzzing machinery itself.
Range ranges['user']¶
This range is occupied by user signature fuses. It is only useful to the fuzzing machinery itself.
Range ranges['reserved']¶
This range is reserved. All fuses in this range must be set to 0.