diff options
Diffstat (limited to 'sys/i386/doc/ata/ata-5')
| -rw-r--r-- | sys/i386/doc/ata/ata-5 | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/sys/i386/doc/ata/ata-5 b/sys/i386/doc/ata/ata-5 new file mode 100644 index 000000000000..c120a39b3736 --- /dev/null +++ b/sys/i386/doc/ata/ata-5 @@ -0,0 +1,189 @@ +5. Interface Cabling Requirements + +5.1 Configuration + +This standard provides the capability of operating on the AT Bus in a daisy +chained configuration with a second drive that operates in accordance with +these standards. One drive (selected as Drive 0) has been referred to as the +master in industry terms and the second (selected as Drive 1) has been +referred to as the slave (see Figure 5-3). + +The designation as Drive 0 or Drive 1 is made by a jumper plug or switch on +the drive. + +Data is transferred in parallel (8 or 16 bits) either to or from host memory +to the drive's buffer under the direction of commands previously transferred +from the host. The drive performs all of the operations necessary to properly +write data to, or read data from, the disk media. Data read from the media is +stored in the drive's buffer pending transfer to the host memory and data is +transferred from the host memory to the drive's buffer to be written to the +media. + + +-----------------------------------------------------+ + | | + | HOST | + | | + +---------------^-------------------------------------+ + | ATA Interface + | _____________________ + |/ | + +------v--+ +------v--+ + | DRIVE 0 | | DRIVE 1 | + +---------+ +---------+ + + FIGURE 5-1: ATA INTERFACE TO EMBEDDED BUS PERIPHERALS + + +-----------------------------------------------------+ + | | + | HOST | + | | + +------+====== AT Bus ======+-------------------------+ + | | + | ADAPTER | + | | + +--------^-----------+ + | ATA Interface + | _____________________ + |/ | + +------v--+ +------v--+ + | DRIVE 0 | | DRIVE 1 | + +---------+ +---------+ + + FIGURE 5-2: HOST BUS ADAPTER AND PERIPHERAL DEVICES + + +-----------------------------------------------------+ + | | + | HOST | + | | + +---------------^-------------------------------------+ + | ATA Interface + +------v-----+ + | | + | CONTROLLER | + | | + +-^----^---^-+ + | | |__________________ Device Interface + | ___|_________________ | e.g. ESDI, SCSI + |/ | | | + +-v----v--+ +-v----v--+ + | DRIVE | | DRIVE | + +---------+ +---------+ + + FIGURE 5-3: ATA INTERFACE TO CONTROLLER AND PERIPHERAL DEVICES + +5.2 Addressing Considerations + +In traditional controller operation, only the selected controller receives +commands from the host following selection. In this standard, the register +contents go to both drives (and their embedded controllers). The host +discriminates between the two by using the DRV bit in the Drive/Head Register. + +5.3 DC Cable and Connector + +The drive receives DC power through a 4-pin or a low-power application 3-pin +connector. + +5.3.1 4-Pin Power + +The pin assignments are shown in Table 5-1. Recommended part numbers for the +mating connector to 18AWG cable are shown below, but equivalent parts may be +used. + + Connector (4 Pin) AMP 1-480424-0 or equivalent. + Contacts (Loose Piece) AMP 60619-4 or equivalent. + Contacts (Strip) AMP 61117-4 or equivalent. + + TABLE 5-1: DC INTERFACE + +------------------------+------------+ + | POWER LINE DESIGNATION | PIN NUMBER | + +------------------------+------------+ + | +12 V | 1-01 | + | +12 V RETURN | 1-02 | + | +5 V RETURN | 1-03 | + | +5 V | 1-04 | + +------------------------+------------+ + +5.3.2 3-Pin Power + +The pin assignments are shown in Table 5-2. Recommended part numbers for the +mating connector to 18AWG cable are shown below, but equivalent parts may be +used. + + Connector (3 Pin) Molex 5484 39-27-0032 or equivalent. + + TABLE 5-2: DC INTERFACE + +------------------------+------------+ + | POWER LINE DESIGNATION | PIN NUMBER | + +------------------------+------------+ + | +12 V | 1-01 | + | Ground | 1-02 | + | +5 V | 1-03 | + +------------------------+------------+ + +5.3.3 Device Grounding + +System ground may be connected to a "quick-connect" terminal equivalent to: + + Drive Connector Terminal AMP 61664-1 or equivalent. + Cable Connector Terminal AMP 62137-2 or equivalent. + +Provision for tying the DC Logic ground and the chassis ground together or for +separating these two ground planes is vendor specific. + +5.4 I/O Connector + +The I/O connector is a 40-pin connector as shown in Figure 5-4, with pin +assignments as shown in Table 6-1. + +The connector should be keyed to prevent the possibility of installing it +upside down. A key is provided by the removal of Pin 20. The corresponding pin +on the cable connector should be plugged. + +The pin locations are governed by the cable plug, not the receptacle. The way +in which the receptacle is mounted on the Printed Circuit Board affects the +pin positions, and pin 1 should remain in the same relative position. This +means the pin numbers of the receptacle may not reflect the conductor number +of the plug. The header receptacle is not polarized, and all the signals are +relative to Pin 20, which is keyed. + +By using the plug positions as primary, a straight cable can connect drives. +As shown in Figure 5-4, conductor 1 on pin 1 of the plug has to be in the +same relative position no matter what the receptacle numbering looks like. +If receptacle numbering was followed, the cable would have to twist 180 +degrees between a drive with top-mounted receptacles, and a drive with +bottom-mounted receptacles. + + +-----------------------+ + | 1| + |40 20 2| + ==+==== Circuit Board ====+== ==+==== Circuit Board ====+== + | 1| + |40 20 2| + +-----------------------+ +.. * Location of pin number stamped as 1 when receptacle mounted upside down + FIGURE 5-4: 40-PIN CONNECTOR MOUNTING + +Recommended part numbers for the mating connector are shown below, but +equivalent parts may be used. + + Connector (40 Pin) 3M 3417-7000 or equivalent. + Strain relief 3M 3448-2040 or equivalent. + Flat Cable (Stranded 28 AWG) 3M 3365-40 or equivalent. + Flat Cable (Stranded 28 AWG) 3M 3517-40 (Shielded) or equivalent. + +5.5 I/O Cable + +The cable specifications affect system integrity and the maximum length that +can be supported in any application. + + TABLE 5-3: CABLE PARAMETERS + +-------------------------------------+------+--------+ + | Cable length of 0.46m (18 inches) * | Min | Max | + +-------------------------------------+------+--------+ + | Driver IoL Sink Current | 12mA | | + | Driver IoH Source Current | | -400uA | + | Cable Capacitive Loading | | 200pF | + +-------------------------------------+------+--------+ + * This distance may be exceeded in circumstances where the + characteristics of both ends of the cable can be controlled. + |