PC Card (originally PCMCIA) is a credit-card-sized expansion interface developed for laptop computers and embedded systems, governed by the PC Card Standard published by PCMCIA/JEITA. The connector is a 68-pin card-edge type arranged in two rows of 34 contacts at 1.27 mm (0.050 in) pitch; all card types share the same 85.6 mm × 54.0 mm footprint, differing only in thickness (Type I: 3.3 mm, Type II: 5.0 mm, Type III: 10.5 mm). The original 16-bit mode (PCMCIA 2.x) supports 5 V or 3.3 V Vcc with an 8- or 16-bit data bus, whilst the 32-bit CardBus extension (introduced in PC Card Standard 5.0, 1995) operates at 3.3 V only, 33 MHz, with bus mastering delivering up to 132 MB/s. The final edition, PC Card Standard Release 8.0 (PCMCIA/JEITA, April 2001), added the CardBay interface, a 1.8 V Vcore definition, and a redefined Vpp.
68 PIN MALE Connector at the controller
68 PIN FEMALE Connector at the peripherals
| Pin | Memory | I/O+Mem | Description |
|---|---|---|---|
| 1 | GND | GND | Ground |
| 2 | D3 | D3 | Data 3 |
| 3 | D4 | D4 | Data 4 |
| 4 | D5 | D5 | Data 5 |
| 5 | D6 | D6 | Data 6 |
| 6 | D7 | D7 | Data 7 |
| 7 | CE1# | CE1# | |
| 8 | A10 | A10 | Address 10 |
| 9 | OE# | OE# | Output Enable |
| 10 | A11 | A11 | Address 11 |
| 11 | A9 | A9 | Address 9 |
| 12 | A8 | A8 | Address 8 |
| 13 | A13 | A13 | Address 13 |
| 14 | A14 | A14 | Address 14 |
| 15 | WE# | WE# | Write Enable ??? |
| 16 | READY | IREQ# | |
| 17 | Vcc | Vcc | Vcc |
| 18 | Vpp1 | Vpp1 | Vpp1 |
| 19 | A16 | A16 | Address 16 |
| 20 | A15 | A15 | Address 15 |
| 21 | A12 | A12 | Address 12 |
| 22 | A7 | A7 | Address 7 |
| 23 | A6 | A6 | Address 6 |
| 24 | A5 | A5 | Address 5 |
| 25 | A4 | A4 | Address 4 |
| 26 | A3 | A3 | Address 3 |
| 27 | A2 | A2 | Address 2 |
| 28 | A1 | A1 | Address 1 |
| 29 | A0 | A0 | Address 0 |
| 30 | D0 | D0 | Data 0 |
| 31 | D1 | D1 | Data 1 |
| 32 | D2 | D2 | Data 2 |
| 33 | WP | IOIS16# | |
| 34 | GND | GND | Ground |
| 35 | GND | GND | Ground |
| 36 | CD1# | CD1# | Card Detect 1 |
| 37 | D11 | D11 | Data 11 |
| 38 | D12 | D12 | Data 12 |
| 39 | D13 | D13 | Data 13 |
| 40 | D14 | D14 | Data 14 |
| 41 | D15 | D15 | Data 15 |
| 42 | CE2# | CE2# | |
| 43 | VS1# | VS1# | |
| 44 | RSRVD | IORD# | Reserved / IORD# |
| 45 | RSRVD | IOWR# | Reserved / IOWR# |
| 46 | A17 | A17 | Address 17 |
| 47 | A18 | A18 | Address 18 |
| 48 | A19 | A19 | Address 19 |
| 49 | A20 | A20 | Address 20 |
| 50 | A21 | A21 | Address 21 |
| 51 | Vcc | Vcc | Vcc |
| 52 | Vpp2 | Vpp2 | Vpp2 |
| 53 | A22 | A22 | Address 22 |
| 54 | A23 | A23 | Address 23 |
| 55 | A24 | A24 | Address 24 |
| 56 | A25 | A25 | Address 25 |
| 57 | VS2# | VS2# | |
| 58 | RESET | RESET | Reset |
| 59 | WAIT# | WAIT# | |
| 60 | RSRVD | INPACK# | Reserved / ??? |
| 61 | REG# | REG# | |
| 62 | BVD2 | SPKR# | Battery Voltage 2 / Speaker ??? |
| 63 | BVD1 | STSCHG# | Battery Voltage 1 / ??? |
| 64 | D8 | D8 | Data 8 |
| 65 | D9 | D9 | Data 9 |
| 66 | D10 | D10 | Data 10 |
| 67 | CD2# | CD2# | |
| 68 | GND | GND | Ground |
Notes
- The connector is a 68-pin card-edge type with two rows of 34 contacts at 1.27 mm (0.050 in) pitch.
- All PC Card types (I, II, III) use the same 68-pin connector and 85.6 mm × 54.0 mm card footprint; only the card thickness differs.
- CardBus (32-bit) cards carry a gold ridge on the dorsal surface and use a shallower keying notch that prevents their insertion into sockets which support only 16-bit cards.
- Vcc (pins 17 and 51) is 5 V in legacy 16-bit mode or 3.3 V in 3.3 V 16-bit and CardBus modes.
- Vpp1 (pin 18) and Vpp2 (pin 52) are optional programming-voltage rails; +12 V is applied if flash programming requires it, otherwise they track Vcc or are left unconnected.
Signals
- GND — Signal and power ground (pins 1, 34, 35, 68).
- D0–D15 — 16-bit bidirectional data bus (D8–D15 used only in 16-bit word-wide accesses).
- A0–A25 — 26-bit address bus; enables up to 64 MB of linear address space in memory-mapped mode.
- CE1# — Card Enable 1; selects the card for even-address (low byte) accesses.
- CE2# — Card Enable 2; selects the card for odd-address (high byte) accesses in 16-bit mode.
- OE# — Output Enable; strobes data onto the bus during a memory read cycle.
- WE# — Write Enable; strobes data into the card during a write cycle.
- READY / IREQ# — In memory mode: READY indicates the card can complete the current cycle. In I/O mode: IREQ# is the interrupt request line to the host.
- Vcc — Supply voltage; 5 V or 3.3 V depending on card and host voltage sense negotiation (pins 17 and 51).
- Vpp1 / Vpp2 — Optional programming voltage rails (pins 18 and 52); typically +12 V for flash erase/program, otherwise tied to Vcc or left unconnected.
- RESET — Host-driven reset; forces the card to its initialised state.
- WAIT# — Card-driven wait state insertion; extends bus cycles when the card cannot complete in time.
- REG# — Attribute Memory Select; distinguishes accesses to the card’s CIS (Card Information Structure) attribute space from common memory.
- CD1# / CD2# — Card Detect 1 and 2; pulled low by the card to signal physical presence to the host socket controller.
- WP / IOIS16# — In memory mode: Write Protect (indicates card is write-protected). In I/O mode: IOIS16# signals that the addressed I/O resource is 16-bit wide.
- IORD# — I/O Read strobe (I/O mode only; pin 44 is Reserved in memory mode).
- IOWR# — I/O Write strobe (I/O mode only; pin 45 is Reserved in memory mode).
- INPACK# — Input Acknowledge (I/O mode only; pin 60 is Reserved in memory mode); asserted by the card to indicate it is responding to an I/O read.
- VS1# / VS2# — Voltage Sense pins; the card pulls these to ground in a defined combination to indicate whether it requires 5 V, 3.3 V, or both (pins 43 and 57).
- BVD1 / STSCHG# — In memory mode: Battery Voltage Detect 1, indicates first-level low-battery warning. In I/O mode: STSCHG# (Status Changed) interrupt line used by modems and similar I/O cards.
- BVD2 / SPKR# — In memory mode: Battery Voltage Detect 2, indicates second-level (critical) low-battery warning. In I/O mode: SPKR# carries an audio signal routed to the host speaker.
- RSRVD — Reserved pins (memory mode); must be left unconnected by the card.