STC89C52RC-40I-LQFP44

@@ -0,0 +1,88 @@+# STC89C52RC-40I-LQFP44++**STC Micro** · Microcontrollers (MCU/MPU/SOC) · LQFP-44(10x10)++STC89C52RC-40I-LQFP44 from STC Micro, in a LQFP-44(10x10). Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.++## Pinout++| Pin | Name | Type | Function |+|---|---|---|---|+| 1 | P1.5 | bidirectional | Standard quasi-bidirectional I/O port PORT1[5]. Internal weak pull-up; drives/reads CMOS level. |+| 2 | P1.6 | bidirectional | Standard quasi-bidirectional I/O port PORT1[6]. Optionally connects to external crystal for the on-chip USB-serial helper circuit in some board layouts. |+| 3 | P1.7 | bidirectional | Standard quasi-bidirectional I/O port PORT1[7]. |+| 4 | RST | input | Active-high reset input. HD-version parts have an internal 45k-100k pull-down to GND; hold high for at least two machine cycles to reset the MCU. |+| 5 | P3.0/RxD | bidirectional | P3.0 general-purpose I/O; alternate function RxD = UART1 serial data receive input. |+| 6 | P4.3/INT2 | bidirectional | P4.3 general-purpose I/O; alternate function INT2 = external interrupt 2 (falling-edge or low-level trigger). |+| 7 | P3.1/TxD | bidirectional | P3.1 general-purpose I/O; alternate function TxD = UART1 serial data transmit output. |+| 8 | P3.2/INT0 | bidirectional | P3.2 general-purpose I/O; alternate function INT0 = external interrupt 0 (falling-edge or low-level trigger). |+| 9 | P3.3/INT1 | bidirectional | P3.3 general-purpose I/O; alternate function INT1 = external interrupt 1 (falling-edge or low-level trigger). |+| 10 | P3.4/T0 | bidirectional | P3.4 general-purpose I/O; alternate function T0 = Timer/Counter 0 external clock/count input. |+| 11 | P3.5/T1 | bidirectional | P3.5 general-purpose I/O; alternate function T1 = Timer/Counter 1 external clock/count input. |+| 12 | P3.6/WR | bidirectional | P3.6 general-purpose I/O; alternate function WR = active-low external data memory write strobe (for MOVX instructions). |+| 13 | P3.7/RD | bidirectional | P3.7 general-purpose I/O; alternate function RD = active-low external data memory read strobe (for MOVX instructions). |+| 14 | XTAL2 | output | Output of the internal inverting oscillator amplifier; connect to the second lead of the external crystal. If an external clock source is used on XTAL1, XTAL2 outputs the buffered clock and may be left floating. |+| 15 | XTAL1 | input | Input to the internal inverting oscillator amplifier; connect to one lead of the external crystal or directly to an external clock source. |+| 16 | GND | power_in | Digital ground (0 V reference). |+| 17 | P4.0 | bidirectional | Standard quasi-bidirectional I/O port PORT4[0]. Present only on LQFP-44/PLCC-44 packages (not on PDIP-40). |+| 18 | P2.0 | bidirectional | P2 quasi-bidirectional I/O with internal pull-ups. Doubles as high address byte A8 when accessing external memory via MOVX @DPTR / MOVC. |+| 19 | P2.1 | bidirectional | P2 quasi-bidirectional I/O; doubles as external address bit A9. |+| 20 | P2.2 | bidirectional | P2 quasi-bidirectional I/O; doubles as external address bit A10. |+| 21 | P2.3 | bidirectional | P2 quasi-bidirectional I/O; doubles as external address bit A11. |+| 22 | P2.4 | bidirectional | P2 quasi-bidirectional I/O; doubles as external address bit A12. |+| 23 | P2.5 | bidirectional | P2 quasi-bidirectional I/O; doubles as external address bit A13. |+| 24 | P2.6 | bidirectional | P2 quasi-bidirectional I/O; doubles as external address bit A14. |+| 25 | P2.7 | bidirectional | P2 quasi-bidirectional I/O; doubles as external address bit A15. |+| 26 | P4.4/PSEN | bidirectional | P4.4 general-purpose I/O; alternate function PSEN = Program Store Enable, active-low strobe for external program memory reads. |+| 27 | P4.5/ALE | bidirectional | P4.5 general-purpose I/O; alternate function ALE = Address Latch Enable output for demultiplexing the low address byte on P0 during external memory access. Also acts as PROG programming pulse input during Flash ISP. |+| 28 | P4.1 | bidirectional | Standard quasi-bidirectional I/O port PORT4[1]. Present only on LQFP-44/PLCC-44 packages. |+| 29 | P4.6/EA | bidirectional | P4.6 general-purpose I/O; alternate function EA = External Access Enable. Internally pulled up to VCC: floating or tied high starts execution from internal Flash; tied to GND starts execution from external program memory. |+| 30 | P0.7/AD7 | bidirectional | P0.7 8-bit quasi-bidirectional I/O (open-drain after reset; requires 4.7k-10k external pull-up when used as GPIO). Doubles as multiplexed low address/data line AD7 during external memory access (no external pull-up needed in bus mode). |+| 31 | P0.6/AD6 | bidirectional | P0.6 open-drain quasi-bidirectional I/O; doubles as multiplexed address/data line AD6. |+| 32 | P0.5/AD5 | bidirectional | P0.5 open-drain quasi-bidirectional I/O; doubles as multiplexed address/data line AD5. |+| 33 | P0.4/AD4 | bidirectional | P0.4 open-drain quasi-bidirectional I/O; doubles as multiplexed address/data line AD4. |+| 34 | P0.3/AD3 | bidirectional | P0.3 open-drain quasi-bidirectional I/O; doubles as multiplexed address/data line AD3. |+| 35 | P0.2/AD2 | bidirectional | P0.2 open-drain quasi-bidirectional I/O; doubles as multiplexed address/data line AD2. |+| 36 | P0.1/AD1 | bidirectional | P0.1 open-drain quasi-bidirectional I/O; doubles as multiplexed address/data line AD1. |+| 37 | P0.0/AD0 | bidirectional | P0.0 open-drain quasi-bidirectional I/O; doubles as multiplexed address/data line AD0. |+| 38 | VCC | power_in | Positive supply. 5V for STC89C52RC (operating range typically 3.8-5.5 V); 3.3V for STC89LE52RC (2.0-3.6 V). Decouple with 100 nF + 10 uF close to the pin. |+| 39 | P4.2/INT3 | bidirectional | P4.2 general-purpose I/O; alternate function INT3 = external interrupt 3 (falling-edge or low-level trigger). |+| 40 | P1.0/T2 | bidirectional | P1.0 general-purpose I/O; alternate function T2 = Timer/Counter 2 external clock/count input. |+| 41 | P1.1/T2EX | bidirectional | P1.1 general-purpose I/O; alternate function T2EX = Timer 2 capture/reload trigger control input. |+| 42 | P1.2 | bidirectional | Standard quasi-bidirectional I/O port PORT1[2]. |+| 43 | P1.3 | bidirectional | Standard quasi-bidirectional I/O port PORT1[3]. |+| 44 | P1.4 | bidirectional | Standard quasi-bidirectional I/O port PORT1[4]. |++## Key specifications++| Parameter | Value |+|---|---|+| Manufacturer | STC Micro |+| Package | LQFP-44(10x10) |+| Category | MCU |+| Pins | 44 |++## Ordering variants++- `STC89C52RC-40I-LQFP44`+- `STC89C52RC-40I-LQFP44STC89LE52RC-40I-LQFP44`+- `STC89C52RC-40I-LQFP44STC89C52RC-40I-PDIP40`+- `STC89C52RC-40I-LQFP44STC89C52RC-40C-PDIP40`+- `STC89C52RC-40I-LQFP44STC89C52RC-40I-PLCC44`++## CAD (KiCad official)++- Symbol: `STC89C52RC-40I-LQFP44`+- Footprint: `Package_QFP:LQFP-44_10x10mm_P0.8mm`+- 3D model: LQFP-44(10x10) (KiCad packages3D, STEP)++## Provenance++Data extracted from the manufacturer datasheet, not a distributor listing:++- **Datasheet:** [STC Micro datasheet](docs/stc89c52rc-40i-lqfp44-datasheet.pdf) (1691 pp, sha256 `fac7be430b93e2dd`, retrieved 2026-08-17, tier: lcsc)+- **Datasheet language:** Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.+- **Extractor:** `ds2sf` (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.+- **CAD:** KiCad official libraries (CC-BY-SA 4.0).++[Datasheet PDF](docs/stc89c52rc-40i-lqfp44-datasheet.pdf)