Hi all, thanks for your answers.
Lattice MachXO2:
The smallest device f the family is the XO2-256HC (3.3V with onboard LDO and flash). It has 256 Luts and 2kb of RAM (could be useful to buffer the data). It is available in 48-QFN (40 IO available) and 100-TQFP (55 IO available). This should be enough for my application.
Unlike Actel (now Microsemi) Igloo, the fabric isn't flash-based but is RAM-based:
The MachXO2 devices also provide flexible, reliable and secure configuration from on-chip Flash memory. These
devices can also configure themselves from external SPI Flash or be configured by an external master through the
JTAG test access port or through the I2C port. Additionally, MachXO2 devices support dual-boot capability (using
external Flash memory) and remote field upgrade (TransFR) capability.[...] the time taken for configuration and entry into user mode is specified as Flash Download Time (tREFRESH)
LCMXO2-256 0.6 ms
LCMXO2-1200 1.9 ms
Even though it saves cost on the BoM not having an external SPI flash, the boot up time isn't instantaneous, and the bigger the device is, the longer it takes (normal).
The price starts at $1.08 on
Newark: "Available until stock is exhausted") then ramps up quickly on other distributors: $2.28 on
Mouser and $2.83 on
Digi.
I like the chip, but I don't feel confident in it's long term availability.
Altera MAXII:
The smallest device in the family is the EPM240 (thanks obiwanjacobi).
Searching for some pricing, I can't find anything cheaper than $5 per unit. See on
Octoparts.
I've checked on eBay, but I'm sure you understand I can't buy (from China) on eBay to source my components for manufacturing in Europe.
To summarize, at this point I'd rather stay with good old 7400 TTL logic, than going for pricey, long-term risky chips.