diff --git a/docs/constraints.md b/docs/constraints.md
index 67c8ddd7..dead8780 100644
--- a/docs/constraints.md
+++ b/docs/constraints.md
@@ -9,11 +9,18 @@ The iCE40 architecture supports PCF constraints thus:
 
     set_io led[0] 3
 
-and the ECP5 architecture supports a subset of LPF constraints:
+and the ECP5 architecture supports a subset of LPF constraints (for details see Lattice Technical Note "FPGA-TN-02032 1.3"):
 
     LOCATE COMP "led[0]" SITE "E16";
     IOBUF PORT "led[0]" IO_TYPE=LVCMOS25;
-
+    IOBUF ...  DRIVE=4|8|12|16; // currently LVCMOS33 and LVCMOS33D only
+    IOBUF ... OPENDRAIN=ON|OFF;
+    IOBUF ... TERMINATION=50|75|150;
+    IOBUF ... DIFFRESISTOR=100; //for differential IO only
+    IOBUF ... CLAMP=ON|OFF;
+    IOBUF ... PULLMODE=UP|DOWN|NONE;
+    IOBUF ... SLEWRATE=FAST|SLOW; //outputs only
+    IOBUF ... HYSTERESIS=ON|OFF;
 
 ## Absolute Placement Constraints
 
diff --git a/ecp5/docs/primitives.md b/ecp5/docs/primitives.md
index f7f97d16..6c346ab2 100644
--- a/ecp5/docs/primitives.md
+++ b/ecp5/docs/primitives.md
@@ -2,46 +2,43 @@
 
 nextpnr-ecp5 currently supports the following primitives:
  
- - **ALU54B** (limited support, must be manually placed)
- - **CCU2C**
- - **CLKDIVF**
- - **DCUA**
- - **DDRDLLA**
- - **DELAYF**
- - **DELAYG**
- - **DP16KD**
- - **DQSBUFM**
- - **DTR**
- - **ECLKSYNCB**
- - **EHXPLLL**
- - **EXTREFB**
- - **GSR**
- - **IDDR71B**
- - **IDDRX1F**
- - **IDDRX2DQA**
- - **IDDRX2F**
- - **IOLOGIC**
- - **JTAGG** (untested)
- - **L6MUX21**
- - **LUT4**
- - **MULT18X18D** (cascade functionality not supported)
- - **ODDR71B**
- - **ODDRX1F**
- - **ODDRX2DQA**
- - **ODDRX2DQSB**
- - **ODDRX2F**
- - **OSCG**
- - **OSHX2A**
- - **PCSCLKDIV**
- - **PFUMX**
- - **SEDGA** (untested)
- - **SIOLOGIC**
- - **TRELLIS_DPR16X4**
- - **TRELLIS_ECLKBUF**
- - **TRELLIS_FF**
- - **TRELLIS_IO**
- - **TRELLIS_SLICE**
- - **TSHX2DQA**
- - **TSHX2DQSA**
- - **USRMCLK**
-
+ - **ALU54B** - 54-bit ternary adder/subtractor (limited support, must be manually placed)
+ - **CCU2C** - 2x LUT4 with carry logic
+ - **CLKDIVF** - clock divider
+ - **DCUA** - dual channel 3/5Gbps SERDES
+ - **DDRDLLA** - 90° delay for DQS or clock for DDR interface
+ - **DELAYF** - configurable signal delay
+ - **DELAYG** - simple signal delay
+ - **DP16KD** - true dual port block RAM
+ - **DQSBUFM** - DQS control for DDR memory
+ - **DTR** - die temperature readout *notice: The IO-names in the FPGA Libraries Reference Guide 08/16 are wrong*
+ - **ECLKSYNCB** - edge clock stop/synchronisation
+ - **EHXPLLL** - phase-locked-loop
+ - **EXTREFB** - reference clock input buffer for external clock for SERDES
+ - **GSR** - global set/reset interface
+ - **IDDR71B** - 7:1 input gearbox
+ - **IDDRX1F** - generic 1:2 input DDR
+ - **IDDRX2DQA** - DDR2/3 memory 1:4 input interface
+ - **IDDRX2F** - generic 1:4 input DDR
+ - **JTAGG** - JTAG access to fabric
+ - **L6MUX21** - 2 input multiplexer for LUT6 and above
+ - **LUT4** - 4 input Look Up Table
+ - **MULT18X18D** - DSP multiplier (cascade functionality not supported)
+ - **ODDR71B** - 7:1 ODDR implementation
+ - **ODDRX1F** - generic 2:1 output DDR
+ - **ODDRX2DQA** - memory 4:1 output DDR primitive for DQ outputs
+ - **ODDRX2DQSB** - memory 4:1 output DDR primitive for DQS outputs
+ - **ODDRX2F** - generic 4:1 output DDR
+ - **OSCG** - internal oscillator
+ - **OSHX2A** - memory 4:1 output DDR primitive for address and command
+ - **PCSCLKDIV** - clock divider for SERDES clock outputs
+ - **PFUMX** - 2 input multiplexer for LUT5s
+ - **SEDGA** - allows checking configuration data for soft-errors, see TN1268 (untested)
+ - **TRELLIS_DPR16X4** - 16x4 LUTRAM
+ - **TRELLIS_ECLKBUF** - internal edge clock buffer
+ - **TRELLIS_FF** - SLICE flipflop
+ - **TRELLIS_IO** - tristate IO, mapped by Yosys from BB, IB, OB, etc
+ - **TRELLIS_SLICE** - logic SLICE (2x LUT4, 2x FF, 2x MUX2, CCU2 carry)
+ - **TSHX2DQA** - tristate control for DQ data output for DDR2 and DDR3 memory
+ - **TSHX2DQSA** - tristate control for DQS output
+ - **USRMCLK** - provides access to SPI flash clock (MCLK)