Parallel Advanced Technology Attachment (PATA) Flash Drive
Overview
Disk on Module (DOM) are flash drives with either 40 or 44 pins IDE/Standard ATA Interface USB or SATA Interface to be used as a computer hard disk drive (HDD). The flash-to-IDE converter simulates a harddisk, and therefore the modules can be used without additional software or drivers. DOMs are highly reliable as they do not have any moving parts like regular hard disks and are small in size and light in weight. However, after a disk crash in traditional hard disk, some data may still be recoverable by scanning the physical media using specialized equipment, but there is no known method to recover lost data from a physically damaged DOM. Currently storage capacities range from 32MB to 32GB with various form factor including vertical or horizontal orientation. The DOM is generally plugged directly to the motherboard.[1]
Part Description
Part #: DOM EDC4000 IDE 44Pin Horizontal Type A is comprised of a 44 pin embedded disk card and a IDE interface platform
Unit Price: $91.000
Interface: 44pin IDE/ATA
IDE Transfer Mode: PIO mode 0-4/UDMA mode 0-4
Burst Speed Rate: 66.6MB/sec.
Operation Temp: -10°C~+70°C(Standard)
Vibration: 5G(7~2000Hz)
Shock: 50G/10ms
MTBF: >3,000,000 hours
Read/Write : 80/75Mbs
R/W Endurance: 2,000,000 times
DC Input Voltage: 3.3V-5V
ATA-TQM pinouts
| 40 Pin # | ATA-4 PIN NAME | ATA-4 HOST CONNECTION | Host <> Device | STK sheet 5 name | TQM name | PCB requirements | |
|---|---|---|---|---|---|---|---|
| 1 | RESET- | “ | IDE_RESET- | ATA_RESET | |||
| 2 | Ground | GND | GND | ||||
| 3 | DD7 | “ | <> * | IDE5V_DD7 (10K pulldown) | EXT_AD7 | 10K pulldown | |
| 4 | DD8 | “ | <> * | IDE5V_DD8 | EXT_AD8 | ||
| 5 | DD6 | “ | <> * | IDE5V_DD6 | EXT_AD6 | ||
| 6 | DD9 | “ | <> * | IDE5V_DD9 | EXT_AD9 | ||
| 7 | DD5 | “ | <> * | IDE5V_DD5 | EXT_AD5 | ||
| 8 | DD10 | “ | <> * | IDE5V_DD10 | EXT_AD10 | ||
| 9 | DD4 | “ | <> * | IDE5V_DD4 | EXT_AD4 | ||
| 10 | DD11 | “ | <> * | IDE5V_DD11 | EXT_AD11 | ||
| 11 | DD3 | “ | <> * | IDE5V_DD3 | EXT_AD3 | ||
| 12 | DD12 | “ | <> * | IDE5V_DD12 | EXT_AD12 | ||
| 13 | DD2 | “ | <> * | IDE5V_DD2 | EXT_AD2 | ||
| 14 | DD13 | “ | <> * | IDE5V_DD13 | EXT_AD13 | ||
| 15 | DD1 | “ | <> * | IDE5V_DD1 | EXT_AD1 | ||
| 16 | DD14 | “ | <> * | IDE5V_DD14 | EXT_AD14 | ||
| 17 | DD0 | “ | <> * | IDE5V_DD0 | EXT_AD0 | ||
| 18 | DD15 | “ | <> * | IDE5V_DD15 | EXT_AD15 | ||
| 19 | Ground | GND | GND | ||||
| 20 | (keypin) | NC | NC (key pin) | ||||
| 21 | DMARQ | “ | < | IDE5V_DMAREQ | ATA_DRQ | 10K pulldown | |
| 22 | Ground | GND | GND | ||||
| 23 | DIOW-:STOP | “ | IDE5VIOW | !ATA_IOW | |||
| 24 | Ground | GND | GND | ||||
| 25 | HDMARDY- | “ | IDE5V_IOR | !ATA_IOR | |||
| 26 | Ground | GND | GND | ||||
| 27 | DDMARDY- | “ | < | IDE5V_IOCHDRY | ATA_IOCHDRY | 1K pullup to 5V | |
| 28 | CSEL | GND | Slave/Master (330 pulldown) | 330 pulldown | |||
| 29 | DMACK- | “ | IDE5VDACK | !ATA_DACK | |||
| 30 | Ground | GND | GND | ||||
| 31 | INTRQ | “ | < | IDE5V_INTHD | ATA_INTRQ + | ||
| 32 | reserved | NC | NC (NP 0R0 to !IDE5VIO16) | ||||
| 33 | DA1 | “ | IDE5V_DA1 | EXT_AD17 | |||
| 34 | PDIAG- | NC | !IDECBLIDFP | NC | 100k pulldown & 47n cap | ||
| 35 | DA0 | “ | IDE5V_DA0 | EXT_AD16 | |||
| 36 | DA2 | “ | IDE5V_DA2 | EXT_AD18 | |||
| 37 | CS0- | “ | IDE5V_CS0 | !LP_CS4 | |||
| 38 | CS1- | “ | IDE5V_CS1 | !LP_CS5 | |||
| 39 | DASP- | NC | IDE_HDACT (also to FLACT) | NC | |||
| 40 | Ground | GND | GND | ||||
| 41 | VCC - Logic | VCC | VCC_5VP | 100u + 100n bypass | |||
| 42 | VCC - Motor | VCC | VCC_5VP | 100u + 100n bypass | |||
| 43 | GND | GND | GND | ||||
| 44 | NC | NC | NC | ||||
Functional Description
Transistors
Q4
Manufacturer part#: BSS84
Digi-key part#: BSS84P L6327
Package: SOT-23
Voltage threshold @ Id: 2V @ 20µA
Unit Price: $0.4600
This part was chosen for its low threshold voltage and its availability on digikey
Transistors
Diode
LED11011 is a Green Led (per Andrew).
Q1006
The NTR4101P is a P-Channel Mosfet (Per Andrew)
Resistors
R1046
This is a current limiting resistor with calculated value 470 Ohm.
R1105
R1040
CSEL pin is connected to ground through this resistor. Its value was chosen to match the value found on the STK5200 schematic
R1041
Used for impedance matching between driver and device, this pull up resistor value was increased from 1kohm to 4.7Kohm (per Andrew)for noise margin improvement i suppose.
R1042
A 10K pulled down resistor is required at the host (DMARQ pin.) (Not sure why we have a 4.7K instead)
R1106
A 10K pulled down resistor is required at the host (INTRQ pin.)
R1045
The ATA Spec recommends using either a PU or PD 10kohm resistors at pin DD7 for UDMA configuration as shown below in the schematic from the ATA-SPEC (Rev 18) attached below
R1047,R1049,R1057,R1058-R1068, R1050-R1056, R1094-R1100,
These resistors are used for impedance matching. In fact, according to the ATA-4 Spec, careful impedance matching between the host and the connected device is required for proper UDMA operation. Their values were directly taken from Table 5 of the ATA-4 Spec and listed down below.
| Signal | Host Termination | Device Termination |
|---|---|---|
| HDMARDY | 22 ohm | 82 ohm |
| STOP | 22 ohm | 82 ohm |
| CS0-, CS1- | 33 ohm | 82 ohm |
| DA0, DA1, DA2 | 33 ohm | 82 ohm |
| DMACK- | 22 ohm | 82 ohm |
| DD[10:0] | 33 ohm | 33 ohm |
| DMARQ | 82 ohm | 22 ohm |
| INTRQ | 82 ohm | 22 ohm |
| DDMARDY- | 82 ohm | 22 ohm |
| RESET- | 33 ohm | 82 ohm |
Capacitors
C1038, C1039
These are bypass capacitors used for noise attenuation at VCC. Using two capacitors of different values allows selective attenuation of noise at different frequencies (low frequency noise and high frequency noise...)
Their values were picked to reflect the original design on the STK5200.
Resources and References
[1] Wikipedia